I guess I would like to ask: What feats enable a character concept that doesn't exist if feats are disallowed?
1. Alert - No new conceptual design space. Player can already be play an alert character by having a good perception and a good initiative.
2. Athlete - No new conceptual design space. Player can already play an athletic character by having a high strength and high athletics.
3. Actor - No new conceptual design space. Player can become a good actor and attempt to mimic peoples speech by having a good performance skill and a high charisma.
4. Charger - This feat doesn't even try to add anything to character concept. It adds pure mechanical crunch pure and simple.
5. Crossbow Expert - No new conceptual design space. Can still play any character with a crossbow as his weapon (the feat makes it mechanically possible to do so and not suck)
6. Defensive Duelist - No new conceptual design space. Pure mechanical design space.
7. Dual Wielder - No new conceptual design space. A character can always hold two longswords and attack with whichever one he prefers (perhaps a magical one that does fire damage and a magical one that does ice damage). The feat does make it mechanically not suck to wield two such weapons compared to a Greatsword or a Longsword and shield.
8. Dungeon Delver - No new conceptual design space. The game without this feat already gives plenty of ways to be a good trap finder and handler which is all the feat attempts to enhance.
9. Durable - No new conceptual design space. Same concept is enabled by taking a high constitution.
10. Elemental Adept - This feat only adds things to the mechanical design space. Conceptually this feat can't add anything as it only allows a PC to bypass a mechanical rule.
11. Grappler - No new conceptual design space. You can make a good grappler with any character that has a few hand and a good athletics score.
12. Great Weapon Master - No new conceptual design space. In a featless game you can still make a character that uses two handed weapons. He can still use them well. In fact this feat actively takes away design space by being so good that anyone who now wants to be really good at using two handed weapons now needs this feat.
...
Anyways the point is that a featless game enables all the same character concepts. as a game with feats. Feats do allow existing rules to be bypassed that caused some character concepts to be sucky without actually having to fix the sucky rule in the first place. Example: A crossbow user and part of crossbow expertise that allows you to load more than once a turn. Feats also allow an extra layer and mechanism for a character to become decent at some task he may have struggled to be good at due to other tasks he has committed to being good at. This sounds like it should be a good thing, but it is not. The more resources you have to spend at something to be an expert at it the fewer things you have the opportunity to become an expert at or nearly an expert at. Further it creates the dilemma where the DM basically allows the expert to nearly auto succeed most every check or he ups the difficulty of the checks and anyone that isn't near expert level struggles to ever make the check. If an expert at something auto succeeds then you don't need to invest in whatever the expert is doing. If the expert is the only one with a legitimate chance of success then likewise you also don't need to invest in doing it.
Since selective list there, which you then use to make a sweeping statement.
Which also involves ignoring the fact that the majority of those that don't afd new conceptual space allowing you to confidently state "this is what my character does" rather than "this is what my character does DM/rolls permitting."