First of all, I think using the 3-2 as your base defense every game was a huge strategic mistake. No doubt there were teams where the 3-2 was the way to go, but there is equally little doubt that there were some teams that you should've played a 2-3 against.
Another strategic error (and one you repeated for next season) was scheduling sim teams. You are in a conference filled with sim teams, thereby guaranteeing yourself a bad SOS. You need to counteract that by scheduling a tougher non-con filled with human teams. They don't all have to be world beaters, but taking on any additional sims is a bad mistake. That's why you can win 19 games and still have an rpi that isn't PIT worthy.
(Now that I look, you've repeated that mistake for your entire tenure. A bunch of seasons w. 18-22 wins and rpi's that never got at an at-large bid, and often not even a PIT. That's just inexcusable.)
As for the sf, I agree that he underperformed this season, mostly from 3p. But he only took 49 3p's, so with that kind of sample size, if he'd hit just four more 3p's over the course of the season, his 3p percentage goes from 30 to 39% and all of the sudden looks a lot different. Overall I agree that he underachieved, but not horribly so.
(He also overachieved as a jr by shooting 51% from 3p. The sample size in HD just isn't big enough to produce reliable individual results from one season to the next. It's not a senior slump, per se, just coming up on the wrong side of the dice. Sometimes that happens as a soph, sometimes jr, sometimes sr. It just stands out a heck of a lot more when it happens during sr year.)
Smarter scheduling and gameplanning guarantees you a spot in the postseason.