I feel these are all nice game options (for unrated that is). The 50 card minimum would be a nice option but I don't feel it should be something that's mandatory.

As far as features I'd like to see added, I'd love to see in custom games at least an option for 3-4 player every man for himself match kind of like magic the gathering, I'd also like to see an option in custom games for 2 vs 2 which could be very interesting and after all what could it hurt to try this in unrated games