Just some random calculations to decide if the cost actually IS good 8) .
Accumulative Damage, you and your opponent drawing 1 card/turn.
Turn 1: 1, 0 Charges
Turn 2: 4, 2 Charges
Turn 3: 9, 4 Charges
Turn 4: 16, 6 Charges
Turn 5: 25, 8 Charges
Turn 6: 10 Charges when you draw a card, so it is rewound. Or 36, 10 Charges if upped.
Accumulative Damage, you have 3 hourglasses and stop as soon as it is at 6 charges.
Turn 1: 4, 3 Charges
Turn 2: 11, 6 Charges
Turn 3: 20, 8 Charges
Turn 4: 10 Charges when you draw a card, so it is rewound. Or 31, 10 Charges if upped.
Actually seems pretty fair to me. It would average a 5 attack creature over 5 turns (6 attack over 6 turns upped) if didn't use any precogs/hourglasses, and when combined with hourglasses average a 7 attack creature over 3 turns and a 8 attack creature over 4 turns upped. Seems good, actually.
Still considering the 1/0 thing though. Might make it 2/0 since it would effectively cost 6 time (5 to play it, then 1 to hasten and make the creature permanent).