I absolutely wouldn't mind if there were a lot of variation when it comes to progression. That would be a great thing. As any Mariner fan can attest, even "can't miss" prospects have a tendency to "miss" a LOT.
But I do think it should be tied to bad performance or major injury. Hultzen IRL just had major surgery and might not ever be good again. But, in this case, he pitched really well in his 1st year and then, not only did he lose 10 pts on his overall, the Mariners just let him go. He may be able to get back to 86 but it won't be with my team.
It should also go the other way. I'd love to see a C prospect suddenly turn into an all-star level player. I'd also like to see big jumps be possible. Some guys do gradually improve every year but most have one year where their performance increases dramatically.
As for the AI, I hope they've fixed some things but I'm not holding my breath. I haven't seen much improvement the past 5 years. As a programmer myself, they seem like easy things to fix but I don't know what kind of systems and restrictions they're dealing with.
Maybe I'll look into that player lock thing this year. I'll have to see how it's implemented.