its true that its unrealistic, but we would need to consider the long term impacts to the game.... the games economy, team structures and financial viability, the Overextension tax, merchanidising. these would all be affected by allowing multiple people to be trained during a week.
Why? Because instead of just having 1 or 2 guys get training per week, you end up with 4-5. or more! And then you end up with more players with better skills and bigger salaries, and... EVERYONE will have this. Therefore the transfer market will be flooded with more players who have better skills, this will cause massive transfer price fluctations. As a user, I will be training multiple guys who next season, ALL bump in salary, therefore i have to offload partially trained guys, this will again flood the market and cause massive transfer market issues.
More people will have access to more 'trained' personell, which means they can have a bigger Tax Exemption, which will counter-act the actual point of that change.
So yer im just giving you some examples of how even a change which brings the game to be more like 'reality' in fact could cause massive economic issues with the game.
I do however :) I do like the idea of the coach with sub-skills (or like a super-skill) in offense or defense minded training. That would be good.