Well, I see posts about people complaining about how in PVP, people just wait and then wipe everyone out with one spell. So, power creep has made the game a little stale, possibly?
By putting restrictions, it would force players to adapt more to the cards in hand and plan a strategy based on what is there, instead of discarding down to the spells they know they will automatically get.
You want to fish for that one big boomer? Take your chance, slow and steady might with the battle.
I think it might add a depth of strategy to deck construction, and how one plays PVP which could add to the enjoyment of the game.
Just kicking it around...it seems like it could add a layer of complexity, but not too complex, which could make the game more fun?