I've never used critical fumble rules, but I do have an idea to mitigate the problem of master warriors making more mistakes. Critical fumbles only occur if every attack taken that turn (or as part of that attack action) is a natural 1. This way, any class with extra attack would become less likely to fumble, as they'd need to critically fail twice or more in a row in order to fumble. I still don't love it, but it's an option that I haven't seen mentioned before and I know some players love them some fumble rules. Personally, I think a 1 is a good opportunity to playfully describe a comically bad miss, but there's no need for further mechanical consequences.

One ruling I'll probably use if a player decides to try a called shot, like hitting a basilisk's eyes to blind it or damaging a flying creature's wing to limit its flight, is to roll 2d20. If either is a natural 20, you pull off the shot (9.75% chance of pulling it off; alternatively, maybe a hitting PF2-style crit of AC+10 would also work). If not, treat it as a normal attack at disadvantage, using the lower d20. This is up to the DM's discretion on whether it can be attempted and what kind of consequences are achieved. The idea is it takes a critical-level effect to do a special attack like this, but this way you can up your chance of the critical effect, at the expense of the effectiveness of your attack if you miss.