There's a thing I like to do in my games: Offer players options to de-randomize situations. For RM, I call this "take the 50". This just means: Don't roll the dice, just take 50 as a result - for instance, on your attack roll. This generally works excellently, especially for unimportant NPC's, but I haven't tried it with critical hits yet (where it would mean to have one fixed mediocre but guaranteed effect from a critical hit if the attacker so desires), but I believe it would actually work fine for some situations (and as the GM, I can always have NPC's not use it when things get sluggish).
This works better in RM than in many other games, actually, because RM's beautiful roll-over mechanic is a lot less binary than most "you made it" systems.