I don't know how you would objectively evaluate this, at least the way you framed it Kass. How do you set a bar or expectation for anyone before they step on the floor for us?
You can very easily measure progress by certain stats, ppg/rpg/apg, etc. This often translates to the most influential stat, minutes per game. Without doing anything analytical, I suspect there are very few guys who don't look better statistically year over year. Notable exception here might be DWill last year vs his junior year. I'm sure there are others.
As someone who goes to every home game, I can confidently say that we have tons of examples of guys who look better year after year, and we aren't waiting until their fourth year to see it.
I think the idea that guys develop quickly or slowly is important in differentiating everyone here, TBone. Our coaches should be able to make guys develop more quickly, and help them be "useful participants" in games sooner rather than later -- the more of these guys who are good sooner should give us a deeper roster. This has to do with scouting (selection) and coaching (development).
First, with scouting, I am sure they have some ratings system that would cover how each prospect they are recruiting should pan out. They should roughly be able to assess where they are coming into their college career, and they should also assess where they should be able to go with their coaching.
If they think some guys are going to take 3 seasons to develop, to be useful in their 4th year (think Rick Edwards), that might be very useful in that 4th year. Rick was a very strong player his 4th year, but was relatively inconsequential in his years previous (when going up against the likes of a Jason McKinney, who he couldn't beat out). His peak was pretty good, but his career was just not that great. He had a medium-high ceiling, and was mostly low relative to his peak performance for the better part of his career.
We could look at a guy like Jarod Stevenson, who had a very high ceiling his whole career, but only touched it his senior year. He became untouchable his senior year, after three years of "underperforming," relative to his ceiling. That said, he was perfectly decent, at least scoring-wise, his 1st, 2nd, and 3rd years. But, he was certainly underdeveloped, and most likely definitely under-schemed.
On the other hand, look at a guy like Eric Poole. He came in and was pretty solid his freshman year. He didn't change much (stat-wise) in 4 years. But his contributions each of those 4 years was pretty steady, and was very "useful" over 4 years, relative to the rest of his teammates. I would argue that he was practically at his ceiling, relatively, from his freshman year onward.
Are there ways to measure this? Not exactly -- what is someone's "potential," anyway, other than some way of looking at their skills and working to get the most out of them? Some people make the most of their skills sooner rather than later, and you know what you are getting, and you might not get much more than that ever. Others reach their peaks later, and take a serious jump. There are always variables that can inject themselves into the equation (coaching change, scheme change, growth spurt, etc.) This is all part of how I think players develop, and the effect that coaches can have on their play.