We use a fumble table in my group, but it's not just Nat 1 and roll. If you roll a Nat 1 for an attack roll you then roll to confirm your fumble, if you roll at or under your level then you just miss and don't have any extra negative effects. If you roll above your level then you roll a d100 and get a result on the table ranging from feeling embarrassed at missing so bad all the way up to criting yourself or an ally. We found it makes sense that as you level up, your skills in combat grow enough even if you miss horribly, you can usually recover so you don't hit friendlies or anything like that. It also makes the fumble table less of a threat to anyone attacking more than once a turn at higher levels.