In a deck with hard permission seems really playable, as long as you can keep youself high on life. I think the best comparison is against Jace, not a bad card:
Jace dies to a bolt and attack damage, while this card dies to swords and creature hate. Jace is nullified by revoker/pithing.
Costs are similar. Probably second

is a bit easier than

, but thorn/thalia affect jace alone.
Seer puts a clock of 5 turns at most, probably less because of the life lost because of revealed cards, while jace is slower.
Jace gets rid of BSC and other big creatures; Seer can safely block bears.
Jace kills another jace and it's killed in the same way. That does not apply to seer.
Most of all, jace gets card advantage and quality only to you, not the opponent, even the turn it's played. This is the best argument for jace, but i don't know if it's definitive.