(^-^) Free jersey, and posiblity to sell jersey's

Well I am thinking that usually teams change the jersey every season... when we start the game, we have a "standard" jersey to play at home, and another for out games. So;
1st- Why, we can not have the option to decide if we wanna chaneg it when we win a level (for another standard model, with different colour, model....) ? for example...

2nd- Special jersey's costs tokens, so, why, do not have the option to sell our old jerseys in the market, to win some tokens? ...like with the old players...

suggestions? I've heared that we can share it with friends but.. maybe with special models, of some teams will be good that.