I think you're not giving Alternity enough credit. I've seen it do fantasy (I've done it do fantasy ... er ...) and I've seen it do Supers (but I'll admit, I didn't like that as much). I've used it for Modern and Sci-Fi and I'm sure it would take me about ten minutes to do a pulp game with it.
The system is counter-intuitive only in that you're rolling "low", from what I can see. Beyond that it works, really, like a dream. Anybody I've introduced to it loves it and my current group often interchanges Alternity with d20 Modern and (recently) Mutants and Masterminds. Each system has it's attractive qualities. ((But maybe I just like systems, as I got done running a game of Godlike a few minutes ago and liked that too.))
Alternity had its flaws, but you haven't really touched on them. My biggest problem with the system was that the armor system could extend combats beyond my fun threshold, as decent future armor often gobbled up anything but powerful future weaponry. Also PCs were decent at what they were decent in, but absolutely abysmal otherwise. Most untrained skill checks defaulted to trying to hit a 3 or 4 on 1d20+1d4 which is nearly impossible.
But then again we had a weren who picked a lock by rolling double ones on a hefty penalty. When it happens, it happens spectacular and it birthed a long-living story about ... the weren who picked a lock with a fingernail and a prayer. I like good tabletalk game stories.
I can probably "do more" with Modern and some creative house-ruling, but I would hazard to say I could do more with Alternity straight out of the box than Modern pure. Just opening up my Alternity books gives me ideas for days, and I don't really get that feeling from any other system. Had just the right amount of flavor and just the right amount of generic.
--fje