if you could build up 12 mana then you could Otherworldly Journey a big creature you control and then Sway the Stars, essentially giving your opponent a 1 or 2 turn clock to kill your guy before they lose.
that tora card is cool, but damnit Terashi himself better show up in this block, and he better be cool too. I'm tired of seeing Terashi this and Terashi that. Terashi Terashi Terashi!
Well the only real use I see for this is in maybe some kind of new deck with all these akki land-haters, but then again, maybe that'll become a good deck. Time will tell...
it doesnt give you 1 mana when you hit the opponent, it gives you 1 mana per point of damage to the opponent. So if you hit them for 4 with the enchanted creature, you get 4 mana.
You know, its not like the extra mana has to be used for a pumpable creature. You could always just skip through your first main phase, attack to build up a few points of mana, and then tap out during 2nd main phase to cast something big. Seems quite good to me, although not necassarily "hot."
http://www.wizards.com/magic/images/mtgcom/fcpics/features/247_HundredTalonStrike_2983.jpg
mmmm alternate splice costs.