I believe in a golden middle way here to solve a few problems.
Why not:
* speed up training a little for low skills (up to Respectable)
* slow down training a little bit for high skills (Marvelous+, even slower at very high skills)
(a alternative way is to increase the "osmosis"-training a bit, making it a little slower to train the main skills)
* increase the salary more noticably when player have 18+ in skills.
* increase the importance of subskills (mainly handling, driving) in the Game Engine.
In my opinion a player with 18 IS,ID,RB but 2 in HA,PA,DV SHOULD be very easy to defend, since he hardly can bounce the ball once without losing it. Doubleteam a guy like that and he will force many TO:s... I don´t think the Game Engine punishes that enough, as it is now.
I don´t think that there sholud be a salary roof on player level. On team level there already are, kind of. Would you like to build a scoring machine with no D, then go a head. But if you would like to build a TEAM, you should and would aim for a more balanced skillset on your players, with certain skills higher ofcourse to match your selected tactics.