The only thing I don't like about this card is that it can be such a do nothing, either it is closing the game or it is a near blank
Its drawback may look like its very punishing and can allow the opponent to surprise you via a mid-combat spell, but I never really saw that scenario play out since its damage prevention ability is a a conditional static ability so as long as its on when damage is dealt, it wont be prevented. (Thank you, @fenaris!) It usually plays out somewhat like a colorless Ashenmoor Gouger / Chimeric Idol where you typically dont bother trying to block with it (why am I blocking with my aggro guys anyway?) and, if need be, you cast a spell pre-combat to activate it (typically I used a large coin, like a quarter, to denote whether it was on or off)
Even if this spell gets countered you still get four cards with it, likely providing you with future answers
Some exile one player's graveyard, while others exile all of them simultaneously, but even one exiled graveyard is enough to make Umbris scarily big
If there is to be an extra item, such as a Gift Set or other collectors' items, as has been the case with many of the previous sets, it has not been officially announced yet, as of the time of writing
The first is that it doesnt actually give you a chance to tap down the creature, meaning you have to either wait for its controller to tap it or use it while the target is already tapped