Although it may seem a little outlandish, I have an idea which I think could add a bit more excitement to the game and get the manager more involved with those players who are good but not quite good enough for the first squad - often the ones who later request a transfer.
Reserve Team Leagues!
The introduction of a reserve team league, like real clubs have, for players who are good but can't quite break into the first team. It runs at the same time as the first team league but is restricted to 1 match per week.
The leagues should start by reflecting the current first team ones. Promotion or relegation is something which I find to be a hard issue to tackle as it holds 2 options: either the teams are liable to their own independent place in the league (if they finish bottom they are relegated like an independent team) or they play in the league of their first team regardless of their position at the end of the season.
A Monday would be good for this as it is the longest stretch between first team matches and breaks up time nicely for eager managers but could be moved -1 or +1 day due to cup matches.
Friendlies therefore would still be able to be played on Thursdays if a manager wishes to arrange one.
Like friendlies, players should not be prone to fatigue in case they are needed for first team matches. It should take the same system as the SMFA Cup matches where fatigue is not affected but cards do count only for the said league as well as injuries.
There would of course have to be an indicator that the player has made apperances for the reserve team as opposed to the first. Perhaps a simply "R" mark or renaming the reserve clubs, e.g. Queens Park Rangers II, might be a solution to the issue.
Reasons why it should be introduced
Interest & excitement in the game
To keep interest in the game, I think this feature would help add a sense of realism and fun. There would be more managerial work which is the essential part of the game giving managers a way of testing out tactics, set-ups and younger players to help achieve the first team winning tactic.
The reserve team league would also be another interesting competition to follow for managers giving them a little more than just one goal to aim for.
Avoids loss of squad knowledge
Sometimes, when you have what you see as the perfect high-rated squad, you can really lose touch with your players sat on the bench or simply as reserves. As it can really affect playing lower-rated players in your first team, this could help you keep on top of all of that as well as avoid good players falling into the dangerous "unhinged" zone which frustrates a large amount of managers.
Some clubs with players rated 92-94 end up seeing players rated 90-91 wanting to leave when, really, they are future risers with a guaranteed place in the first team after a rating change - this is very frustrating.
Some lower clubs have only 21 players, especially if they were managed and then their manager left. This can leave great players stuck in low leagues with no chance of every moving to a club that you could use their talent to win their league.
As these clubs may need to buy more players to meet the requirements of an 11-player reserve team, this would solve the solution of those players being stuck at clubs and cure the annoyance of those waiting to buy them.
Some managers are even known to cheat by creating 2 accounts just to get the other players out of the 21-player clubs - this is a solid solution.
Instead of good, young players with a decent future receiving 0 apperances every season, this could be an interesting addition to their career statistics. Displaying just like the first team stats, it would give managers an idea of player potential without having to second guess & avoid good players becoming bench warmers for the next 6 season.
Like everything on here, it's just a thought which I think would really benefit SM and would make it that bit better.