Simple change: move the NIH effect from C3 to C1. Why? Fast trapping is an enormous boon not just to the trapper, but to the entire group. I get seriously annoyed by characters that have to stop and search and I'm sure other players get annoyed by my characters that have to do the same. And, well, it just makes trapping 10x more fun when you have it on your trapper.
So, make it easy and cheap to get; elf + 8-9 AP or L27 feat is simply too costly for most builds (or too late to matter much).
IMHO, this tiny change would greatly increase the demand for the tree. Every single trapper will want it rather than only players that want a strong Xbow build. More demand, more income, more money to hire devs to fix things. It's a win for everyone, even those that don't play trappers themselves.