The extra attack is not a fighter class feature in 3.5e. It's just a part of the rules, and all martial characters get it at the same level, with less martial characters like rogues and clerics getting it shortly afterwards.
I think the wonkiest dice I've ever played with for this would be Eclipse Phase. It's a "d100 under skill" system, but uses the number you rolled as degree of success. So it's like blackjack; rolling high is better, as long as you don't bust. That difficulty modifier can turn a roll from amazing to awful. It's not bad, and it's never caused confusion, it's just funny.
A hobbyist in a field no-one else has explored is a leading expert.