Why would you prefer a 45 second clock?
i like(d) the diversity of college bball (compared to the nba). 30 seconds and i think you're pushing up against where continuous offenses are ineffective (honestly, 35 seconds is probably pushing up against that point). take away time to move the ball up court against pressure and a few seconds to run an iso after the offense fails and a defense only has to defend motion for about 15 seconds. that seems too easy. even just diversity in pace is something i enjoy.
30 seconds might lead to more zone d, though. i suppose that would counteract a reduction in offensive diversity.
on top of everything else, college players just aren't that skilled. i don't want to see more relatively bad bball players trying to score in isos or running two man sets. gross. the rules (not rule changes, i can't really detect a visible change) add to the unwatchability. coaches have the choice of hoping one of their unskilled players can somehow score the ball in 30 seconds or just run guys at the rim until someone blows a whistle. the less time there is to run an offense, the more shooting free throws is optimized as an offensive strategy.