Its not a team fight build. and the fully stocked thirster's make up for the lack of health, as well as the heal spell. Its a build were you run in, stealth, surprise, and cut out, or run in help team and cut out.

This is not a build where you stay in one place to get targeted, run in, run out. handle business.

I appreciate the concept you are imparting, but I have to say. 1700hp at L18 is very bad. You will die too fast in team fights to have a chance to get away.

You should consider incorporating a defensive item with good HP. I didn't vote, as this is a new guide, to give you a shot at augmenting =)