I put a lot of time and effort into trying to accomplish this and while my attempt was futile as everytime you sim a season and load a draft class with a particular roster, the average (I'm sure you know everytime you load a draft class in madden the projected rounds change for some players) projected rounds are different every time.
That being said, here are some important things I learned and you should consider before taking on this task:
1. Make everyone leaving early a senior. The ages are pretty random, you can have RS Juniors be 25 years old and RS Seniors be 23, etc. Don't worry about it, it's WAY less of a hassle than trying to get all the guys you want to leave early. Just scrap that idea, trust me lol.
2. In Madden, anyone not a projected round 1 will not have A potential and as such will only be able to be 89 ovr in his career. Not realistic, I know, but keep this in mind when changing ratings around to get the projected rounds for players.
3. When converting from NCAA to Madden ratings, this is what I've found to be the case on average, I will use a player with a 95 overall in NCAA as the converter:
Average round 1 pick is 79, round 2 76, round 3 74, round 4 72, round 5 69, round 6 65, round 7 60
Keep in mind this chart is just so you know how to create a balanced class, if you use the same overall ratings for every position youll end up with half the round 1 picks being DEs, no round 1 off linemen or wide receivers, etc. In short, the higher the converted average overall rating, the lower you're graduating class should be across the board, so DEs should be at most 92, and OT or WR you'll need some 99s to get round 1 and A potential.
QB 95->75
HB 95->73
FB 95->89
WR 95->70
TE 95->81
OT 95->70
OG 95->71
C 95->68
DE 95->83
DT 95->78
OLB 95->76
MLB 95->74
CB 95->75
FS 95->79
SS 95->80
K 95->82
P 95->82
4. This is only for if you're going to draft for every team manually, but you'll notice that Madden has once again not supported 3-4 defenses at all, and the CPU will sign 4-3 DEs to the Ravens or Steelers and draft 4-3 OLBs and so forth, very frustrating! Obviously a simple fix of having 3-4 teams depth chart being NT, 2 DTs, 2 DEs, and 2 ILBs, but oh well.
For now, here's what you need to do to get the right amount of 3-4 players as 14 teams run the 3-4 and 18 run 4-3:
5 DTs need to pack on some lbs and be 325+ NTs (2012 shouldn't be an issue with 350lb guys like Poe and Ta'amu, but later years underclassmen are underweight)
8-10 DTs -> DE
8-10 DEs -> OLB (include guys like Courtney Upshaw who are already OLB in the game in this count, as he's already a 3-4 OLB)
5. I believe size does matter to some extent, which is why it's damn near impossible to get Matt Barkley to be a 1st rounder since he's 6'2, I think it's just harder for guys to have A potential if they aren't the right size for the NFL.
That's all I can think of for now, I'll contribute to the cause after all of the declared underclassmen are known as I was going to revamp Mustang's roster myself to make all of them seniors anyway.
PS- I noticed you added FCS players to random teams, might I suggest adding them to the FBS teams they played for? Janoris Jenkins - Florida, Aaron Corp - USC, BJ Coleman - Tennessee, etc.
Also,
http://www.cbssports.com/nfl/draft/p...kings/TSX/2012 is a good resource for 2013 and later (I usually make the top top guys like Lattimore, Mathieu and Woods juniors so they graduate in 2013, trying to predict 50 underclassmen leaving early for 2013 and later would be tough though)