daggerfall- insane amount of skills,insanely large world, lots of lore and factions. multiple endings to the plot
morrowind- comparatively very small world but balanced out by incredibly detailed lore and landscape. highly detailed guild system. plot fleshed out fantastically. fantastic world. tod remains fairly uninfluenced
oblivion - few skills, low amount of armour slots, removal of cool stuff. low amount of lore, uninspired and repetitive landscape, basic guild system, generic and illogical plot. more emphasis on combat (although by itself the combat was still pretty poor). land is blatantly Tolkienified
skyrim- even fewer skils, removal of lots of stuff even from oblivion, combat is main focus, more conan and less tes, armour designs dont belong in tes.
estimated tes 6- even fewer skills, tiny randomly generated land, most likeley tod trying to imitate the latest fantasy movie with a little tes.
estimated tes 7- skills are combat,stealth and magic. another fantasy movie ripoff with a little tes involved.
(edit: everything they tell us about skyrim is that it is still simplified, the only instances that involve skyrim not being simplified is a dynamic overlay system for warpaint and stuff,the return of enchant and combat. thats it.
/extreme pessimism