1. Not sure why you think that Fain is not being hunted by the Darkhound pack. He's in the Blight now, but we don't know how long he's been there, and he can easily use the Ways to get back and forth between places quickly, though of course the Waygates only go so far north. Moridin said straight out that Slayer was hunting Fain, and there was nothing to indicate how fresh the trail was that the Darkhounds were following. In any case, it had to have been before Fain went to Far Madding, so this POV revealed nothing new in that sense.

2. Also not sure why you would think that Fain obviously didn't send the army of Trollocs. I think it is more obvious than ever that he did, now that we know that Mashadar is a part of him, which gives the obvious connection to Sammael (whose soul was inaccessible to the Dark One because it was corrupted by Mashadar).

3. If RJ uses Fain in a Gollum role, it makes no sense to assume it would be inherently unimaginative. If that is the case, then very nearly every detail of WoT is unimaginative, as it's all derivative to one degree or another. RJ's talent is taking the tropes and twisting them into something new.