Elite Spellbinder
Creature — Human Cleric
Flying
When Elite Spellbinder enters the battlefield, look at target opponent's hand. You may exile a nonland card from it. For as long as that card remains exiled, its owner may play it. A spell cast this way costs more to cast.
3/1

That's actually pretty cool.

So you shoot a card in their hand with a tax bullet, and also make it so it can't come down while you have say Drannith Magistrate

It took me minute to parse this, because I forgot MDFC's exist. Because if you hit one of those with a land on the back they can play the land with no penalty, which is an interesting interaction.

I really like the ability. It's a neat expansion of White's color pie that I hope they explore more.

That said, the exile part seems clunky and the Drannith Magistrate interaction could not have been an intended function. Was there really no better way to do it?

"When Elite Spellbinder enters the battlefield, look at target opponent's hand and you name a nonland card there. The next time that opponent casts a spell with that name from their hand, it costs more to cast."

Would that work?

I think this works better if you're thinking about triggering this ability multiple times (via multiple copies and/or flickering). It prevents memory issues and/or stacking the tax on the same card.

This is where Hearthstone has easier technology.

Yeah, that's fair. I've been playing so much Arena lately that I sometimes forget that you've got to manually keep track of these things if you play paper Magic like a nerd.