Felon: I've seen several teams that should do well not (and two of your teams come to mind immediately: Your EOL Lakers and your 80s team right now). I just have different experiences, though. I certainly could tell a huge difference with my Wilt Trip-Dub attempts (hovering between 50 & 60 ast%) and my normal teams (65-80 ast%) as far as shooting % went. I've also seen HUGE numbers come from other pairings (in our 80s league, someone has Stockton AND Magic in the backcourt. Check out that team's shooting percentages. That Barkley is almost shooting 66%). Also, dh555's team has some super high fg% as well (combined Magic & 89 Jordan). Maybe it's just erratic luck. You and I both know that 82 games is too small a sample size for the sim.
badja: I have no idea how many assists I drafted. The only total I look at is minutes; everything else is advanced or per 48min.
Overall, though, I'm of the opinion that unless you just have tons of cap room, I wouldn't worry about trying to achieve godly assist percentages. Other things are way more important. I know that I saw a team win almost 70 games and fly through the playoffs with barely above 50% ast% (mostly because they had godly boards/threes).