It's entirely possible (even likely) for 3-4-5 to be equally as tough as 3-4-6 but for 3-4-5 to make 6-game series more likely, DUCY?

As for the psychological differences I just always disagree with this type of argument because it seems to assume that professional athletes are weak-minded people who are easily bothered by pressure. Sure there's the occasional Chris Webber who does shrink under pressure but most top athletes have been trained from a young age to not let pressure get to them and perform at least as well when the pressure is high.