D&D 5E How would you replace stat bumps in feats?

[5ekyu]

I want them to be interesting, useful, worth choosing, and - most importantly - fun.

Interesting... my definition is not yours do... no ho there. Might as well want us to tell you which ice cream tastes good.

Useful, worth choosing - again in comparison to what? Current feats have broad differences in balance depending on setting. What's your setting and campaign style? Is it heavy combat minmax damage output or lots social? Are combats more white room slugfests or detailed complex battlefields cuz that affects the balance between gem and mobility. Linguist can be huge or trivial, which is it in yours?

Fun - what is defined as unfunny in your gsme?

If I were to give a generic answer for the main question based on what we now know...

Replace +1 score with "one reroll after seeing the roll before knowing the result on any attack, save or ability score using this ability (recharge at short rest) "

 

[TwoSix]

Resilient is a good example where this method would fail: too powerful! 2 saves? Yes!
This way any PC would choose Resilient at some point (at least my characters...).

Paladins gain the equivalent of proficiency in all 6 saves, that's stackable with proficiency and can be given to other characters within 10' at 6th level. Let's not pretend that even giving out proficiency in all saves at 1st level would meaningfully skew the game.

 

[AkaKageWarrior]

Paladins gain the equivalent of proficiency in all 6 saves, that's stackable with proficiency and can be given to other characters within 10' at 6th level. Let's not pretend that even giving out proficiency in all saves at 1st level would meaningfully skew the game.

"meaningfully skew the game", definitely not, but even small things add up.

The paladin save bonus is a special class feature, a feat is available to everyone, so I wouldn't compare these.

Why I still think it is a little too powerful (2 saves for 1 feat):
When I play an offensive spellcaster (no matter if DM or player) I have a look at my opponents and chose my spells:
fighter types? let's go wisdom save, and so on...
With the prof. in 2 more saves, one weak spot in the high level characters can be covered up: at least one important bad save. With the feat you'll have prof. in DEX, WIS, CON.
If you want to be that good in saves, play a paladin or a monk!