User blog comment:KodachiZero/Why Trading is Bad/@comment-100.9.133.124-20151216043448

Maybe they could do a trading option, where you put up a unit you want and the unit you would like to trade. If somebody is willing to trade the unit you want for the one you put up, they could request for a trade. If both parties agree, then they could trade. But both units have to be the same number of stars so that it's more fair for everyone and it you could choose the unit type you want as well (although the unit you get might not necessarily be the same type as the type you requested).

Sorry if this sound confusing. ・°°・(＞_＜)・°°・.