There is a reason why Peer Through Depths has the Arcane subtype.

i'm slow; why?

A spell that only draws you a card is completely useless except if you're counting the spells you cast or are trying to fill your graveyard. In fact, there are many one-mana cards that do something small AND draw you a card. Peer Through Depths is Arcane so you can try to splice.

Your card is basically just drawing one card plus restrictions.

ah that makes a lot of sense, because of card advantage and such.

Ah, I think SU is referring to Reach Through Mists. I can see that would make his comment a little harder to understand :)

Yes, there exist things like Peek, Leap and Fleeting Distraction that mean a 1-mana nothing-but-cantrip isn't a good idea.

This on the other hand is really interesting. Cantripping removal is awesome unless it's nerfed pretty hard: Annihilate cost 5 mana and was still fine; Zap cost 3 for 1 damage; Electrolyze is very popular at 3 for 2 damage in 2 specific colours.

But the ability to only play the card this turn is a significant drawback. I think this might actually be spot on. Very interesting.

Whoops. I'm sorry about messing up.

This card is really great, I agree. The only thing is that many people might not know whether you can cast an exiled sorcery if it wasn't your turn. And a lot will definitely mess up with lands. Either make this a sorcery, or this should give the exiled card flash. (And by now it's creeping complexity a lot.)

The card feels borderline general power level-wise. It begs to have a deck made to break it, but it's not clearly broken right off the bat.

I suspect it wouldn't be printed as a common, though. Such a big upside is usually uncommon (Turn/Burn, magma jet, punishing fire). At common, making it sorcery would also remove the cases where you can't use the exiled card (b/c it's not an instant).