Read before you postAs we all know, this card was nerfed, so the ability cost is
(for both upped and unupped). Now, why do I find it underpowered?
Let's compare upped mindgate with electrum hourglass:
In other words, you pay a higher cost to draw a card that doesn't form part of your deck (and also, that doesn't form part of your strategy). This card is mostly for fun rather than killing the opponent. How do you know the card will be useful? Will you have the quanta needed for the card? In this last case, you may get your oponent's pillars or you may use a rainbow deck. There are way better uses for aether quanta (quintessence, fractal). I would prefer to get my own cards. In some cases, though, it helps to give a purpose to the unused quanta we end getting in most games.
I also think that electrum hourglass is overpowered, but nobody says so because a lot of decks use it. Think about it, the normal draw rate is 1 card/turn, but with only 1 time quanta (after putting it in play, of course) you can have an extra card. Precognition is more reasonable because you can only use it once.