Foots, that is Feats

This post will not give a hard, mechanical breakdown of every feat that will be in my hypothetical 6e PHB. There's way too much balancing that will go on for that to be feasible. It will, instead, try to theory-craft what makes a good feat, how to build good feats and outline some ideas around that to give possible feats for 6e.

When looking at feats, we have the whole of the 3e/3.5e ecosystem and the 5e ecosystem to look at. I skipped 2e completely but I understand that there were feats in 2e as well. We also have, although it's structured differently, Pathfinder and Pathfinder 2e.

We have a few ideas to bear in mind here: 

• Core or Optional: 5e gave us feats as an optional rule, every other system has them as a core rule.
• Complexity: 5e made them simple. In essence they rely on a simple proficiency at most, although a few are tied to being a given race. Pathfinder 2e goes for Ancestry (race equivalent), general, class, level, tree-like prerequisites (you can only take this feat if you've got that one) and more, and you can only take certain type of feats at certain levels. 
• Balance. Feats should be worth (as far as possible) the same. Not to all builds, but there shouldn't be feats that are broken, so if you don't have feat X for build Y you're at a huge disadvantage. Consider, for example Great Weapon Mastery. Who builds a character that uses a heavy weapon and doesn't take it? Sharpshooter is the same for archery builds. There may be niche builds that take Actor or Keen Mind but they're not in the same league as the others I've mentioned, I would argue even if you're campaign skews social.
• False Choice. I am in favour of choices for players to make about their characters, but the choice between "should I take a feat or an ASI?" is a bad one, or even a false one. There are few occasions where a feat is better, and those occasions are usually because you have an overpowered feat, equally the 5e system punishes players who choose any of a range of characters who are MAD. OK, they are often rewarded for being MAD by having characters who are well rounded (if not actively OP) in their class features, but this isn't a good way to balance a character class IMO. Nor does it make for variety. EVERY monk, at 14th level, ends up being proficient in ALL their saving throws. It's a great ability. Stand near the paladin, and you get to add their Cha modifier too... rock those saves! But needing to boost Dex, Wis and Con? Fat chance of taking a feat to give you a bit of flavour, unless you go vHuman.

So, how do we deal with this?

First, as I've mentioned before, I think we take away a lot of the bad calls 5e made. Feats should be baked in, well balanced and not an option either an ASI or a feat. I don't mind giving you an ASI and a feat at each multiple of 4 levels, but I'm not making you choose between them.

However, I'm broadly not in favour of returning to 3e/3.5e/Pf feat trees. Small trees, where you must have a proficiency and a minimum level, that would let you build up the dodge, mobility, spring attack, whirlwind attack family (I know I've missed some out, but if you played 3e/3.5e you know what I mean) because of level restrictions and other proficiencies I don't mind, but you wouldn't have to have feats. You might find, though, given the proposed skill tree structure, that dodge requires light armour-1 or unarmored defence-1 and light weapons-1 or unarmed attack-1, mobility the same things at 2 etc. so you have to keep training the right combat proficiencies up.

I am broadly not in favour of restricting feats. That's a personal preference and I am open for negotiation on this. If you say Elves get secret weapons training that gives them super-advantage on x... and x happens to include the super-weapon in the game thanks to an unforeseen exploit, then you have just made everyone play an elf. Even if you give every other species the same super-advantage on their species-preferred weapon set. Also, you are playing into lazy stereotypes. Why are Elves trained in long sword, longbow and whatever? Do Elves not produce thieves and assassins? Why are Orcs always trained in battle-axe and maul or whatever? Do they not produce skirmishers and skalds? So if we're going to have these sorts of feats, lets make them sensible. Lets make a (probably high level) Advanced Berserker Tactics that teaches super-advantage with great axe, great hammer, maul say. And a similar one for various other combinations of weapons. You need to be (say) level 15 and have tier 3 proficiency in one of those weapons and tier 1 proficiency in all of them. Your Elven Berserker can take them just as well as your human or Orc and stack them on top of Reckless Attack.

I suggested in my previous post, that the cross-class feats should let you take a proficiency pick from a different class at each level, and possibly give you a free one when you first take it. That's a hard thing to balance from because it's not yet clear what this means in terms of what you gain. However, I have also talked about the Blade Mastery feat as a good feat. For those of you not familiar with it, Blade Mastery gives you: You gain a +1 bonus to attack rolls you make with the weapon; On your turn, you can use your reaction to assume a parrying stance, provided you have the weapon in hand. Doing so grants a +1 bonus to your AC until the start of your next turn or until you’re not holding the weapon and When you make an opportunity attack with the weapon, you have advantage on the attack roll. In 5e a flat +1 to hit is quite big, use your reaction to get a +1 to AC is certainly nice (although you have to choose between it and the third one), and advantage on an opportunity attack instead of +1 AC is also nice. While it may not stay identical in 6e, I think this gives us something to work from. We can start to calculate just how much of an advantage this gives a sword-wielding character at every level and aim our other feats at doing the same sort of thing. GWM and Sharpshooter would both get major rewrites. I haven't done the maths, two things that spring to mind are either a +1 modifier to weapon multiplier on critical (so normally you roll damage and double it for a critical, but you would triple the weapon damage part. If you're a paladin or a hex blade with the right invocation, you wouldn't triple smite damage. Barbarians and Orcs both get something to increase critical damage, this would stack with that.), OR you get +1 threat range. Normally you only get critical on a 20, but this would make it 19-20. Champions and Hexblades get something to change that, this would stack with that. Both could opt to forgo extra damage/improved critical to offset disadvantage (this is similar to the current "no cover" in Sharpshooter, but a bit worse). If we're sticking with the 5e action economy (which I hope we don't) maybe make these choices each take a bonus action? Heavy weapon users don't generally have a lot to do with it, and that makes it easy, archers might have more to do with it, but that's ok. They may or may not need a third thing - because we're balancing to "effective output" if this balances up to the Blade Mastery I'm happy to leave it at that. 

A lot of magic feats that affect attack abilities, I'm looking at Spell Sniper and Elemental Adept come up a bit short. I don't have a sure fire fix for them that isn't subject to balance issues, but one that springs to mind for Elemental Adept is to have similar feats for all forms of magic, so you'd have Fire Adept and Necrotic Adept and Healing Adept and something like, "If you roll under your casting stat modifier on any of the effect dice, you can reroll them. You choose which result to take." So if you get to a +6 Int modifier, you can reroll all the dice you roll for your Fireball spell and take the higher result. Awesome? No. But certainly nice. And probably nice enough to make that the only thing it does and not feel underpowered, although stacking it with the current resistance has no effect, immunity counts as resistance might still just make it to the list, we'd have to see how the numbers work out. This still leaves a batch of skills and role-play feats. They're harder to balance up, simply because you don't have quite the same measure of impact. This starts to rely on feedback from players. But we've got a sort of rubric from Blade Mastery of a flat +1, and either a defensive +1 or a situational advantage on a roll. We might be more generous with social skills, say Bluffer lets you take +1 on Persuade, +1 on Insight if you have succeeded on a Persuade check and advantage on Persuade, Intimidation or Deception checks if you have succeeded on an Insight check against the target. While, in mechanical terms, that's a bit of an edge, it doesn't feel like it overpowers the party Face in a social setting. Does it feel like enough to make it attractive though? Something that lets you Persuade a group might be a better fit, or just an alternative. Similar feats for all the skills should be available, and need to be worked out, so you can sensibly be a Ranger who specialises in Tracking (via a feat) and is actually good at it without requiring something like Expertise as a class feature. The Bard, who actually uses their Performance checks, gets a feat to better at performing, and can probably pick soloist or group performer for advantage on their rolls in that situation to give you even more flavour. And so on.

I'm sure there are more things. Certainly a lot of this needs testing to see how it balances out in terms of impact and attractiveness. Do the out-of-combat skill feats need to go straight to advantage rather than +1 say? It's a big edge, so my feeling is to avoid that, but maybe they need that edge to make them more attractive? Or perhaps they should give +1 to a group of skills, like Bluffer should give +1 to any three of the Cha-based skills or Insight (for example). I don't know what the balance is, but that is the sort of thing I'd be looking at.