The clipping matters to me, but I'm someone who shares pictures here and on tumblr and writes little non-stories for them. That's part of my enjoyment for playing the game. Spending a lot of time paused staring at clipping in TS3 made me have higher hopes for 'smarter sims', 'better routing' etc in TS4 (especially considering all the time they don't seem to be spending on other things....).
Other than doorways (I'm looking at you, University!!), I've been incredibly lucky and never had a lot of issues with sims standing around waving their arms (I do often get sims standing around for an hour changing into another outfit though *sigh*). Going through each other isn't an improvement, at least not to me. My fingers are crossed that things will be better in the version we'll actually be playing but.... I have played TS3 so I won't be holding my breath. :P