I don't mind so much about training; at some point you have to max out.
No improvements would be fine if there was some other way to use cash. Nordeus needs to figure out a way to exchange cash for boosters or use it some other way.
Time will tell, but the Association changes are generally good. It takes away more exploits.

If Nordeus fixed other parts of the game, like the markets and the engine, then people will be more willing to stay and not be turned off by the more minor issues you detail above.