4 minutes is still pretty painful.
Why so slow? Is it still opening to the network path, but using the mapped drive?
if you open 15.1 to the same location, is it just as slow?
Also, after the reset, I assume you know how to copy certain settings back so you aren't at square 1. If not, see this post.
For version 17.0, we're going to have an option in the "Reset user files" window to preserve connections and a few other key settings when you do a reset.