The problem is, all you need to have happen for that to feel not true is a selection of high rolls on the other side. It might be made worse by some of the specifics of that system, but I've watched one player in my 13th Age game get beat like a drum because the D20 just decided on my end it wasn't going to roll anything less than a 16 for about six successive rolls. If you run for a while with a D20 game (or a percentile game, far as that goes), you'll just get that sort of thing. Its not the "one godawful series of open ended die rolls blowing up all over you" you can get in SW (especially with damage) but the effect is much the same.