I'm not privy to the real reason, but I'd expect that it was likely forced on them as a condition of publishing, (Like the 'trying' FO2 temple "tutorial" may have been). :shrug:
The TB improvements are great, but the "tacked on" RT system kind of defeats the point and [IMO] would have been better had they managed to omit it. The Fallout series is not like Myth and the http://www.youtube.com/watch?v=i0t3paCm21E is not like Fallout (though both are exceptional). I don't consider RT of any kind (in Fallout-s) to be an improvement, or something that fans should be made 'used to' ~any more than I'd like a real time non-linear variant of Chess or Go. :shrug:
As far as I remember, the RT combat was implemented because they had to rush out a demo video for a showing at a convention (E3?). They faked a lot of the demo for the video, as you usually do for those sorts of things, and so had things play in real time. That ended up being touted as a feature of the new game by a lot of the people who saw the demo video, so they left it in at the end.
As far as the original post, it's actually my favorite of the "old" Fallout games. The storyline isn't anything to write home about, but the combat and multiplayer is a lot of fun. The combat of both F1 and F2 weren't ever really their strong points, though I do recall spending hours (and hours, and hours) playing a Fallout demo where you play entirely within a single town and end up choosing factions between leather-clad or metal-clad gangs. I enjoyed that fight at least.