I don't get to see enough of the games to take a definitive position, but a few things seems apparent to me. Yes, Jardine hung around to play for 4 years, and got better every year, which I appreciate. His play was noticeably better, but a lot of that was due to his entry level was not good. Even near the end, he put the ball in jeopardy less, but he still did it. Case in point, the Marquette game. GD it, a 4th year PG should know you don't get cute with your footwork near the 10 second line, but he did anyway, and at the worst possible moment. And in the back of your mind, you kept waiting for something like that to happen again.
For a lot of his time at SU, Scoop had Rick Jackson to look for inside, who was a very good low post player. We don't seem to have that option today. The ball seems to be in the hands of 5th year seniors who are concerned about where they'll be next year. It's possible that Coleman could be a low post presence (although not likely quite as strong as RJ), but in the 3 games I've seen this year, the perimeter players don't seem to understand the importance of getting the ball inside, or they just can't get that done. I don't know what's happened to Frank Howard, he seems to have gone Kaleb (another good kid I felt bad that we lost). Maybe he's just not assertive enough to fight for his spot? It's confusing, for he played well and was getting better during the second half of last year.
I thought Ennis needed more time at SU. He had one way to play, which was to dribble around the perimeter until there were 5 seconds left on the shot clock, and then it became "Oh !" time. Drove me nuts. Also, staying for a longer stint might have helped him learn to find his own shot, which I don't think he really did have. A PG needs to have that threat (notice I didn't say "shoot first"), for if when you penetrate they sit in the passing lanes, you have to be able to score when it's necessary. And that helps in so many ways, because once the defense figures out it doesn't have to honor the PG as a scoring threat, they just shut everything else off, and the guy with the ball in his hands most of the time can't score. That's what killed us later on in 2014.
Again, this is just IMHO, and if I'm wrong, feel free to correct me.