What fair enough can replace such feature of the Fighter (Champion)?
Hello everybody,
I find myself in the need of your help once more. 
I'm DMing a 5E game. once a week. In the group there is a fighter. The player wuold like to pick the "Champion" Martial Archetype, but the Improved Critical feature of that build is not compatible with one many-years-long tradition of homebrew rule: crit is a natural 20 only.
The player really likes the Champion. Since it's unlikely to drop such home rule, what I'm demanding is something fair enough to trade the Improved Critical feature with. Any idea?
Many thanks for all your precious advices. Bye!
Poach from the Barbarian and have that improves critical deal additional damage or maybe permit another attack.
I think another attack would be good.
This can really affect the Champion balance when combined with feats that grant extra attacks on crits like Great Weapon Master. For example once the Champ hits 3 attacks and an 18-20 crit range, with advantage he'll nearly have a 30% chance to crit per swing. And with 3 swings per round that's nearly a crit once each round, which then nets a 4th attack. So it's a pretty heavy nerf for greatsword champs and part of their core balance.
Allowing the Champion to use a bonus action for an extra attack might help balance that out. It'd probably be stronger at lower levels and weaker at higher levels and it wouldn't sync up with action surge nearly as well.
for balance, it might be easier to add the things he likes about champion to the battle master subtype? what does he like about champion? if it's mostly flavor, you could add it to battle master and he could pick appropriate abilities that match the flavor maybe?
Hi there. Thanks everybody for your contribute.
Looks like the player is satisfied for swapping the high crit for a +1 damage bonus (+2 at 15th level). What do you think about?