I've been playing Elements for some weeks now, and I have to agree that a mulligan feature would be a really good idea.
Good and bad hands should certainly have an effect on the game (after all, that's why you have a randomly selected hand in the first place), but far too often, especially in higher-level games, you draw a hand with no pillars, making you dead before you get enough quanta out to play your first spell. Not fun.
I'd quite happily simply give each player a single mulligan opportunity (at no disadvantage, with their hand simply reshuffled into the deck and redealt), but having more than one mulligan opportunity with some disadvantage could be cool too.
Reshuffling and redrawing with a reduced hand-size for each mulligan sounds like a workable solution, actually.
But yes, certainly a much-needed feature, I feel.
Ryan