hextech crafting

i'm curious to know if you receive a box for let say ashe, will you never be able to receive a box for ashe again or is it seasonal? another thing, i think its really weird how when you play a champion on rotation that you can't get any hextech bonuses from them, aren't/isn't the rotating champions suppose to get you to play different champion(along with only allowing one box per champion), so why are you penalizing the people trying out different champions then praising them, i think if your playing a rotation champion you should have a 100% chance of getting a key if you win(or some praise) for playing someone your not comfortable with. For the chest let them get chest if they get a A or better or something. i just feel like your doing the opposite of what your trying to do because of the fact it seems your penalizing the people who like to try out different champions. Thats how i feel, please Riot tell me why?