re: Anyone here ever play Dungeons and Dragons? (DnD)

The main differences are in rules and structures and such. The way that classes, powers, skills are used as well as the rules governing combat. The biggest mistake that 4e made, to me, was to try to put a mechanic and "game" around social skills and the more role playing aspects of the game. It really created a poor experience in some ways because, even if you had the role play and did something clever or interesting, if you didn't have the skills to back it up, it fell on its face unless you had a DM willing to move beyond the rules.

3.5 was much less rules oriented but much also so HUGE in scope and idiosyncratic addons and such that it too became confusing.

5 is like a reboot to try to capture the original spirit of the game but also having logical rules that back that spirit up.