Fanaelialae
Legend
13th Age did something vaguely like this, wherein some abilities could only be used on an even attack roll and some on an odds. My understanding is that a lot of people didn't love that.I don’t think I’m seriously proposing this…just brainstorming…but what if every time the character gains/learns a new effect, you assign it to a d20 result. When that’s your unmodified attack roll, you get to use the effect (if applicable). It takes all agency away, but I personally would still find it fun. At high levels you might have a whole table of effects.
When you want to trip an enemy, the master of fighting ought to be able to trip an enemy. He shouldn't have to hope for a 5% chance (after actually hitting).
Although, I actually did once have an idea for a caster designed along these lines. It was intended as a magic system in which magic is chaotic and hard to master. The wizard would start with one spell that "contained" the equivalent of several D&D spells. When you cast it, you would roll for the effect. If you didn't like the effect, you could choose not to have it release and instead continue casting into the next round, trying to force the magic into your intended form. As wizards leveled up, they would refine their spells, trimming spell effects from the list (thereby making the new spell more reliable). I'm not sure it would have worked, but I thought it had some merit. Mostly, IMO, because the randomness would have potentially made it feel more magical. Which isn't really something you want for a martial manuever.