I think spell decks she be able to hold more spells. instead of 64 level 100 deck should be 70-75 and for the size on the screen it would be a little smaller then usual but still at a decent size to still see it
It's not really necessary. The more spells you have in your deck, the less likely you are to get them when you need them, so it's best to keep your deck small.
I would love to have that many cards especially for pvp. I keep running out of cards in pvp especially against balance. I have the entire deck filled up and reshuffle takes all my pips. I vote yes to this idea. Again you can choose to not fill ur deck up so it would not affect the people who said "You won't be able to find anything you need.".