I have thought of two ideas that you might like to use GB
The first and very easy to implement is why don't you introduce a manager of the month and season award like in football for example.
Second idea is to do with the end of season draft. What about using a transfer system with money.
Here's how it goes, depending on where a team finishes in the leauge they get so much money ie last in div 2 gets 60 million and first in div 1 gets 10 million, which they then get to spend on transfers, the reason for the difference in money relates to how good a team is so coming top of div 1 means that they are not going to need to make changes a team that is already the best etc and last in div 2 must mean the team is bad and needs better players to be competive etc. ok what happends is that each manager then decides which players they want to buy and e-mails / leaves a message here, the team manager of the player that they wish to buy and then the two managers then come to an agreement between themsleves about how much they will offer, remembering that they only have so much to spend, once the two managers agree then they simply e-mail or leave a message here for you GB letting you know of the transfer (player and how much for) you then make a note of change and how much each team has left to spend etc. The money then swaps beween the teams like in a normal transfer.
You could also say that other sorts of transfers are acceptable for thoses with less money ie Player + Cash or player for player etc
These means that the lesser teams will be able to out bid the better teams at the start so that the gap between the teams ablity should come down.
Also the amount of work you have to do GB would be minamal as all you need to do it update each team with how much money they have left and make a note of which players have moved where.
As for the acadmey teams well that's up to you, because I can't think of a good way of doing it.
Anyway it's only an idea