Time for me to marathon binge... but Ethan Phillips really sold the villainy of his Ferengi character in "Menage a Troi". So I don't think he's a bad actor, but I'm thinking you have a point about Neelix being abandoned. Heck, even his final episode was a massive stretch.
Also, what were the other actors in the top casting sessions like? Phillips did it the best...
Probably, he fit the suit. Have you ever seen the Voyager excerpts with the original captain? I've seen it once, and it still hurts. The original captain was hired for her name, not her performance, and don't let the propganda fool you, she was replaced once they saw her performance.
Yeah, I saw Phillips do a bit of stand-up at the NYC premiere for "What We Left Behind" and he was pretty entertaining. If the character failed, I don't think the blame can be laid solely or necessarily mostly at his feet. He seemed capable of doing a fine job in episodes like "Jetrel"...but most of the time the writers didn't seem to know what to do with him other than go for humor...with mixed results. I always found the Neelix-Tuvok interactions particularly awkward, and I wish the writers had dropped that particular trope. We all have annoying coworkers to be sure, but Neelix was on the level where I might have filed a complaint with HR.
I felt "Jetrel" was really awful, and rank it in my bottom 5 Voyager episodes. I don't "skip" much, but I have to skip this one. To be fair, James Ssssssslurrryan's voice annoys the living crap out of me, but Ethan Phillips is as much to blame. I know... you're entitiled to your opinion... but really. The character had no chemistry anywhere. Oh, he was in an amusing scene or two, I'm not denying that. But his scenes with Tuvok weren't funny, his scenes with Kes weren't believable, neither were his scenes with Tom, and no one cared when the episodes that revolved around him.
As a show progresses, characters sometimes become "breakout" characters, sometimes they fade. Sometimes a character is supposed to be temporary, but it clicks so well that the character becomes permanent. I firmly believe if the scenes with Neelix worked, he would have been a breakout character. He should have been, and needed to be. But he was played like a boring, hapless boob. If you read the scripts, the words aren't the words of a hapless boob, Phillips interpretation of those word makes it so. I can only assume he was trying to be amusing and funny.
And your last sentences suggests the point, though. His interplay with Tuvok should have been funny, not awkward. In scenes where Tuvok and Tom are teasing each other it works:
Tom Paris : These people have been traveling for 400 years. They've learned a thing or two about living comfortably!
Tuvok : Our systems are more than adequate.
Tom Paris : Ah! I give up!
Chakotay : After only two minutes? Tuvok, how do you do it?
Tuvok : I wait until his own illogic overwhelms him.
These lines are delivered flawlessly, and it is a fun, laugh out loud moment, especially with Tim Russ' deadpan delivery and Tuvok's chemistry with Paris. Now watch the scene in "Tuvix" where the ever "joyful" Neelix tries to get Tuvok to sing, but the song he picks is a Vulcan funeral dirge. The whole scene should have been funny, but is instead awkward and painful, and it isn't Tim Russ fault. There is no chemistry.
What I like about Neelix is often his advice was really good and he had such an interest in the food he was serving. I'll take him over Guinan for sure
Occasional advice late at night in the mess hall, and serving wierd food does not a sucessful ensemble make.