First.. I think it's really sad to see this as the end result for Ashton. Maybe he'll take the Marcus Sales path, get his act together and finish out his career. At a minimum, I hope he finishes out his degree.
Tip, I played football in college and at the WR position. Not tooting my own horn, because I wasn't good and played (if you call it that) at the D3 level. Now, I'll caveat this with the fact that a D1 playbook is likely a little larger than a D3 school, but I can tell you that I've seen both and truthfully, it's no where near double the size. Learning a playbook for anyone isn't like learning quantum physics. It's actually more comparable to learning algebra. I had 3 different position coaches during my time and 2 offensive coordinators. Even at the D3 level, coordinators bring their own style and playbooks. We went from a 65% running offense to a 65% passing offense with the switch. Learning the playbook is one of the easiest tasks to fulfill for a student athlete. It's just another study course. Further, it's not like a WR runs 1000's of different routes. Each play calls for a different route, however, there are 9 core routes and the playcall from the sideline usually tells you what you're doing. For example, in college our coaches would signal in for the QB (pro-form offense - 2 WR's split on each side of the ball and a TE) to call a "495." This meant the WR on the left sideline ran a "4" route, the TE ran a "9" route and the WR on the right ran a "5". Now the "495" would be preceded with other instructions to indicate either who the primary receiver was; the number of steps the QB was dropping; and/or whether it was a designed rollout. Again, not rocket science. Not all OC's use the numbering system, but they use some variation of it. Now, OC's also typically don't run a play that was in the playbook that hasn't been practiced in a while either. So any person, no matter what the position, actually gets multiple angles for attacking learning a playbook.
I apologize if this was all, well duh for you, but I only explained this because mastering a playbook is not all that difficult from a WR perspective. I know for a fact that it's actually even easier from a RB perspective. So to say that the coaches "screwed" Ashton by switching his position every offseason is an absolute joke. Ashton's problem with playing the WR position was two-fold.. 1) He didn't run crisp routes. 2) He tried to rely on his talent more than his coaching. So they tried him at RB and vice-versa. Ashton's problem always seemed to me that he took his talent for granted and didn't put enough effort into being great. Sometimes, an athlete can get by that way, but their talent has to be undeniable (see Michael Crabtree @ Texas Tech). But Ashton's talent wasn't enough to overcome his lack of preparation and effort. As a D1 student-athlete, it seems he may have taken it for granted the fact that he was physically talented enough to play at that level.
Hopefully he didn't throw away his chance at a degree, because it seems that's all he's really going to have to fall back on.