Its because it has a less chance of failing. True, you can get something awful like a wisp, but considering how many cards there are in the card pool makes it very unlikely to provide anti-value, unlike farsight which pulls from a deck of maximum 20 cards and has loads of chances to back fire
At least this doesn't have the "can't cost less than 1" restriction. Seems of the weaker side, but it does only cost 2, so it might be worthwhile. People will have fun with it regardless.
It doesn't even have "Can't cost less than 0 restriction". Although I somehow doubt they would allow for mana gain when drawing 0-2 mana minions. Would be pretty awesome though and would add a reason to maybe actually use that card. Otherwise chance of it fizzling is too high for serious decks.
As if randomness in itself wasn't reason enough to exclude it.
pretty sure it cost 0 if it was a 0-2 cost minion unless the card says otherwise like summoning portal.
Something that I haven't heard said about this card is that if you draw a 2-mana minion then you can just play it immediately. So although that's not a great outcome, you haven't lost anything really - 2 drop for 2 mana.
So its only 1 drops that really screw over this card and they're not too numerous. Obviously anything above 2-mana is a pretty good outcome.
I really like the card.
15% of the card pools are 1-drops. That's still significant.
But I think it's a decent Arena Card, because the randomness of the outcome won't matter so much in a per se already randomized draft. It will pull Legendaries disproportionately, as well, since every card should have equal chances of being drawn.
Another reason it will be a decent Arena card is the upside (A 3 mana Ogre or Archmage or whatever can win games) is very good while the downside (It is a 1 or 2 mana guy) isn't that terrible. I think I actually, in Arena, like this card a bit more than when I first saw it, when I considered upside vs. downside.