Personally I rather dislike "5% of every attempt will be wacky", especially when multiplied by "higher level people are making more attempts, and thus are having more wackiness".
The fighter who makes three attacks a round is going to have three times as many "hilarious fumbles" compared to the lower level fighter only making one.
This is part of why I prefer dice pools over a flat single die system.
My current plan is to wait for my basic coworkers to have kids, and those kids to be old enough to ask "what did you do in the 2020s to fight fascism?". They'll lie and say they did a lot, and I'll burst through the wall to shout "NO THEY DIDN'T. THEY DID SHIT. THEY STAYED HOME AND PLAYED VIDEO GAMES. YOUR DADDY IS A COWARD".
Hopefully somehow this will result in my coworkers dying alone and unloved in a pit of shame or something.
But the reality is their egos are indestructible and they will always think they're good people, and their kids will probably be the same.