1- Injured players: the ratio is too high obviously, but that's not the biggest problem. How the hell can you cure a broken leg or something like that in a couple of seconds with red packs (doctors)?? I mean if you want this game to be slightly realistic then make it impossible to heal stuff like that completely.... Otherwise we get the strong impression that this is all about money making/spending.
Also it shouldn't be possible that players have very serious injurys while stretching on medium. Ajust the injurys to the condition, the kind of training the player is going through and the intensity he is training at.
To be explicit, just make it more predictable -> fair for everyone.

2- Generally the use of red, green and blue packs (connected to point 1):
How can a player get from 1 to 100% health in seconds, i sometimes get the impression that jesus must be working as a doctor in the nordeus universe..If it is too obvious that you can actually buy everything in this game with real life money it gets boring and many players will quit. Don't get me wrong, buying tokens should give you an advantage but good managing should be able to compete with that. In the end the one with the biggest skill should win not the one with the most tokens.
My solution would be: only a limited amount of packs can be used per day for each player otherwise it is possible to cure a 15 days injured 1% health and morale player only with the use of tokens to 100%...

3- friendly matches, enough said.

4- the strenght of a team:
players that have played and trained together for a long time should perform considerably better in matches than a team of new bought ones.

5- paying tokens for your own youth players is kind of stupid.....