It sounds to me like you want the D20 system. Replace bonus dice with static modifiers and higher=better, that's D20 in a nutshell.
Well, higher=better is simply more intuitive. There's a reason why it was adopted, and it wasn't because of change for the sake of change. It's the same reason people decried THAC0.
As to the dice part, I don't disagree it's in large part due to the D20 system. It's an elegant system, which is something I think a lot of game designers either by choice or by ignorance to the problem, ignore. However, it is a distinctive part of the Alternity system, and that's why I'm ambivalent. I will point out though that Alternity was basically
the basis for the D20 system anyway. Roll a d20, add a modifier, done. The only difference is the lower=better holdover from TSR, and dice instead of static steps. As to the last part, if you believe that a d6 = 3.5*, then it's even more the same thing.
I don't have too much time to go into detail right now (stupid work) but I think my biggest perceived issue is that rolls are already swingy due to the d20, and with the modifier being swingy too, I think it creates too many situations where something logically should work (d20-d20, for example) but in practice that still leaves a large window for failure given such a hefty bonus. Like I said, it's perceived though; if someone wants to run numbers, I'd love to hear it.
* As in, does a dX = the average of the die. I do not believe that is a fair conversion - a static bonus is a known quantity, and IMO almost always preferable as a player.