Am I misreading this? If you play 4 lances, that means you would get 4 additional lances... not 7. It would potentially (perfect drawing scenario) allow you to play 6 fire lances and then 6 more the next turn though. The fact that you can have RoL to generate enough
for this card and then use cremation to convert them to
for your lances is just mean. Works with drain life to a lesser extent, and ice bolt a bit less than that even.
Also, just thought about using this with heal. Lots of HP gain there. Good for mass creature control (rewind or congeal... or double up on the number of times you can congeal/shockwave a big enemy). Or it could guarantee two turns of survival if you use a Miracle and have a lot of
towers/RoL out. Lots of potential, but I think the fire bolt scenario is the only one that could really make it OP.