So TES fans like me who never played those games can play them without having to deal with the DOS crap.
The first TES game I played was Morrowind. I've been very curious about playing Redguard. I downloaded a demo for it and I couldn't even play that. Apparently I need to practically engineer my computer by downloading a bunch of stuff to be able to play it.
Indeed making Redguard work on XP might be frustrating (even if I was able to do that just by setting the compatibility mode to Windows 98, but that may be just because I'm lucky): if I recall correctly, anyway, it should be possible to use a program called Gildos to run it successfully, but you might also http://www.uesp.net/wiki/Redguard:Installation_guide or do a search with google (I came up with some video guides showing how to make it run). Daggerfall and Battlespire can be run quite easily by using Dosbox, as Robbio already said: the only requirement is a quite powerful PC, especially for the latter (but, if [stress the if] I remember correctly, there was a CVS dosbox version which increased the performance dramatically with Battlespire)
About the rerelease: it won't happen. I'd be the first to appreciate an XP port of Daggerfall, but I doubt it'd be even possible to do that; not to mention that Bethesda definately isn't interested in releasing it again.