In its unique way, a very impressive thread!
1. The Kes character was in fact extremely hard to write for because in her personal interactions with other characters, the other characters all loved her and were instantly swayed by her marvelous wisdom and angelic goodness. In Resolutions, for instance, she instantly persuades Tuvok to turn back for the Captain and Chakotay. Jennifer Lien is so cute and that voice is so gorgeous that in one sense you don't mind Kes sucking the drama right out. But it was Kim's confrontation with Tuvok that was more exciting. Petitions to the skipper are the first step to mutiny, after all. And thematically speaking, it was Kim testing Tuvok's resolution that made sense. Pretty much all her interactions with other characters followed this rather Mary Sue-ish pattern. This was dramatically dull.
Worse, the logical possibilities for dramatic development led Kes away from the rest of the crew or the ship. Nine year life span meant every relationship with the others was doomed to end. Psychic powers meant all forms of physical jeopardy should have been short circuited and resolved by Kes. Plust, psychic powers academy wasn't on Voyager. It's not accident that Cold Fire posed the choice of leaving the ship. Worst of all, it was never very clear exactly why Kes was there, going someplace strange to die with strangers met along the way. In the end, until we really understood why Kes abandoned the Ocampa we didn't have a real character.
2. Kim was a token. The thing about the People magazine shoot was that it would have made firing the token embarrassing. Wang apparently no more liked the show than Beltran, and seems to have acted out his frustrations, but the producers slapped him down hard.
As for being incompetent, that surely explains why Timeless was such a piss poor episode.

Incidentally, I've read reports that Robert Duncan McNiell couldn't handle the technical dialogue. I'm not sure they could have filmed some scripts without Wang to cover that.
On the other hand, as attractive as Lien was, she was very young and her performance at the center wasn't always compelling. Mostly I attribute this to the Mary Sue (or Pollyanna, as stated earlier in the thread,) aspect of the character. But in Warlord, I'm sorry, doing a lot of jumping really doesn't quite spell man in a woman's body. Before and After was by far the best Kes episode, and it was strongly characterized by a rather simple sentimentality in her performance. It was entirely correct and very effective but it wasn't much different from every single Kes adoration scene before and after.
3. Much of Voyager was amazingly cheap in production values. A lot of the writing talent was spent on covering this up. Plus Berman is apparently good at knowing how to allocate the budget for proper effect. I really do believe that an iron determination to cut payroll was a main factor in terminating someone.
4. I've read that Johnny Phillips was convinced Neelix was going to get the ax. But as few as Neelix' starring episodes are, they were some of the best episodes that Voyager did. Keeping Neelix over Kes was a no-brainer, and apparently the producers did have some brains.
5. However, given that the weakness of the Paris and Torres characters was a gaping hole in the series, they really should have given thought to disposing of one of those characters. McNiell, I should have thought. He couldn't make any of the repeated efforts to salvage the character work. Dawson at least always had screen presence, even with much less to work with.