About his toughness, guess what: when they say beware, only moon silver harms the creature, other arms don't cut so deep- they mean it. And stat boosts in human form are there to make sure poor naked peasants aren't easy prey when it's not that time of the month, as is the "transformation on injury" effect- though I agree, their agility could be dialed back a bit, even a demigod dwarf of steel can't hit them without becoming a vampire. And your point regarding the insta-infection is valid, and easily remedied by giving START:sometging other than 0 to the interaction.
Also, since apart from minor issues like the above, werebeasts being the bastard sons and daughters of Chuck Norris appears to be a feature in Genesis, my advice to cure severed nerves or missing limbs is this:
1) become a vampire. It's important to watch the name- you should get a vampire, not a lame-ass lamia or demoniac. Those have their physical attributes frozen, vampires don't. This step is relatively easy as they are frequent, and villagers will often do the hard work for you.
2) now, you have some nice increased attributes, and [NOT_LIVING] creature token. Go searching for towers, preferably using a lot of sneaking. If you find a tower, just lie down and sneak in, the zombies will let you crawl under them and the necromancers/pyromancers/druids won't notice you. Pick up and read any book you find, until you have it's powers.
3) if you found and read a Druid secret book, jackpot. You now have an aquired ability: Transform into Direwolf. It will heal all your injuries, and is actrivated purely at will. Also, enjoy Toughness bonus that comes with being a Druid.