Quote Originally Posted by rferries View Post
Many of the spells are a bit too powerful at lower levels, so I'd rule something like you can't use particular cards until you've reached an appropriate character level.
Fair enough. How high do you see as being appropriate? Generally speaking, access to level 3 spells starts at level 5 (for, e.g., wizards, clerics and druids). Perhaps below this you could just take out the royal cards? Possibly also capping the deck at 2 to 7 below level 3...

I also see the deck as appealing even to casters given how much versatility it provides.
True, everyone likes more spells. Even when it's just one random option per day.

Perhaps an ongoing side-quest during a campaign,where characters discover more and more of the cards?
That could work.