Seeing as how I never played Diablo 2 (or it's predecessor) I cannot comment about it's gameplay, but from my time playing the Baldur's Gate games and Fallout, I think the most time I spent on statistical comparisons was rolling (and rerolling) a character in BG2 so I had stats decent enough to get by, because it seemed like if you didn't min/max you'd end up dead more often than not. I found the practice very tedious, and by Gromnir's viewpoint (back from the BIS board days), it was more sensible to use an editor if you were going to "cheat". I agree with him in principle, but at the time I didn't know about any editors, had never used one before, and figued that if I kept rerolling at least I could pretend I was working within the bounds of the game to create a halfway decent character. Rolling attributes remains, to this day, my least favorite aspect of cRPG's.
Fallout was a great deal easier for me to get interested in because it had a point buy type system (not sure it's the correct term since I've heard it used with PS:T only), the weapons and armor system made more sense to me, the combat was wholly turned-based, and overall the setting was less ambiguous and alien. Perhaps I'm more attuned to Fallout's ambience since I'm more interested in sci-fi than fantasy (though I read and enjoy both), but I think a great deal of my enjoyment is derived from the simplicity of the game design, both interface and concept, and how much time I have to spend preparing to play vs. actually playing.
In short, I don't mind doing a little number crunching or weighing the pros and cons of various equipment (it can be fun sometimes if it's not excessive), but I'm not going to chart out attributes, or anything else, just to play a game. I'm more likely to stop playing a game that gets too involved in statistical analysis or rote strategies and not finish (Baldur's Gate) than a game that lets me handle situations more openly (Fallout). Granted the publisher and developer already got the money out of me, but it then becomes a buyer beware situation for any future titles, and that's the greatest strength of the consumer market.
-Reklar
(a Fallout/RPG fan)