It would be nice if you could swap players with your guild mates when necessary and swap them back when finished.

I don't think this would be good, in my opinion. You'd get a top guild player with level 40+ players loaning them to some bloke in tier 1 so he can win that league with ease...

Unless ofcourse, level caps are introduced, so level 1 can only have 10 star players, level 2 20 and so on...

Alternatively, this could work if (combined with the star/ranking idea) if players were 'sold' to guild members, but it would have to cost more recruiter points to use this service. The giver would get a token sum of recruiter points, say 1000, but 10% more would have to be given as a contract manager fee or some other name. This would make it less financially worthwhile, whilst still however guaranteeing that a guild member gets the bloke, rather than anyone on the auction...