But if the card pool is all little tricks and no power cards, there'd be one faucet of variety lost.
Don't really like cards with hidden abilities. Maybe if the card text changed with the element, or if there were just one ability.
Fifty? That's demanding supernovas.
honestly i dont trust the players to design/determine the limits of power cards, new posters even less so. dragons have the highest base atk in the game, but dont have any abilities or a good atk/cost ratio. trying to make trump cards is kind of like posting song lyrics on your facebook status, you may appreciate it, but nobody else does. its an exercise in futility and wasted thought/effort.
the problem with 'other' cards is that without a high cost, a nova/supernova pays for it quickly, with high costs they are necessary. this is why powerful 'other' creatures probably wont work.