Seems like alot of work for a spell that is already as good as fireball and lightning bolt and in conjunction with Spectral Hand is way better.
Besides, I believe it breaks the damage cap set by the DMG for a 3rd level spell. Technically you're ok with the 10 dice damage cap, but no spell beneath 5th level uses d8's for damage. Then you throw in the "+1 per caster level" and its broken. And thats BEFORE you add in all your other stuff.
Furthermore, your spell allows you to heal in addition to all that. VP grants temporary hit points for a reason, because arcane spells aren't supposed to heal you, just buff you until the cleric can do his work. Heck, an actual vampire doesn't even heal from his life sucking, just grants him, you guessed it, temporary hit points. Arcane magic doesn't heal, with very few exceptions and those options are WAY higher level than 3rd. I think there is something at 8th level, but even that forces you to sacrifice spell slots for all of 2 points per level of the spell sacked, whoopedy doo.
The spell as written is perfect. Yes it effects one target and you have to touch them, but you get those hit points added to yours and they can't save against it or evade or resist in ANY way except SR which trumps ALL 3rd level spells.
You can dislike the spell as is all you like, but its balanced as is. If you want to change it in your game, have fun, but just remember that you're twisting something thats already fair simply because you like the spell and want it to do more, not because there is anything wrong with it.
Cheers
