Well, after about 15 seasons in manager mode, I've figured out the weakness in the trading AI. Just so I don't get hammered, I don't look for weaknesses to exploit them (in the long run), I look for them in order to provide feedback to help improve the computer's ability.
The computer places MUCH less importance on prospects in this version. After four seasons of trading two-three star established players for 5-star prospects, my minor league system now has a score of 612, with the next closest team having a score of 85. My team has a payroll of 65,000,000 and is winning 110-115 games just about every year. When my players get old enough to demand high salaries, I simply trade them for 3-4 more 5-star prospects and continue the trend. It takes about 7-8 years to really get rolling with this strategy, but over the long haul, no computer-controlled team can touch you.
Is this something that can be tweaked? Would simply raising the importance the computer places on prospects solve this? Not sure. I'm not very knowledgable when it comes to trading algorithms, but it seems like this is something that would be beneficial to improve. I know the obvious answer is, "Don't abuse the stinking system!" but I don't always have that much self-control!
I love the addition of manager mode so that a blown bargaining deal doesn't tempt me to add an extra year to his existing contract. Now we just need to get rid of the "prospect loophole."