I read the first one and had no desire to continue the series.
[sarcasm]
I mean, you get someones mother and brother killed in front of them, but it's your true love, so they can can forgive you, right?
[/sarcasm]
It might be simpler to just graft some thumbs on you. As for transforming into things, there tends to be a a lot of side effects, as well as it leaves you more open to manipulation. Although we have been working on some ways to stabilize the process.
I just finished Throne of Glass today, I almost did not because it slowed down a lot from the middle towards the end. But it got significantly better towards the last 50 pages.