I read a few of the comments here, but I will post my own reply to the original post.
People who "hate" gunners do so because they have absolutely no frakking idea how to use them.
A good gunner, with the right rounds goes a very long way, on pretty much ANY ship, with ANY loadout.
Read Geo's post on page 1 for a really good description.
To reiterate,
Only the boring ships require 3 engineers (with the exception of the Mobula, but even that is up for debate...)