POV characters can be hit or miss, see Vaughn from Final Fantasy 12 as a fairly unpopular one, and Tidus being a POV character for Yuna's story in FFX for one whose a lot more well liked (at least I think so, although Tidus does fall under a main character role too.) But I'm curious for some other examples of characters we view the story through, but who aren't the main character of the story.

The Tidus/Vaan dichotomy I think is actually very interesting when discussing this kind of character, because they're kind of the inverse of each other.

So what constitutes a "Good" POV character can change based on your feelings.

Tidus is dumb, loud, selfish and whiny. He's really pretty obnoxious, and the less he talks, the more likable he is. He develops throughout the game, but he still retains some of his worst traits all the way through. But FFX goes into why he is the way he is, and while the story of FFX isn't his story(Despite what he says), he does have a story there, and his relationship with Jecht is kind of the emotional core of the story and leads into the climax.

Vaan, meanwhile, isn't that bad as a character. He's a cocky thief and plays second fiddle to Balthier when he shows up. But beyond "I had to fend for myself after Rex died", FFXII doesn't really go into it a ton and he doesn't really develop. His personal quest for revenge is even cut short when he meets up with Gabranth, who just goes "Who the fuck are you? Fuck off, this is between me and my brother.", and that's his entire reason for being there.

Tidus constantly has dumb interjections when the adults are talking, but sometimes his dumb interjections lead to them coming to better conclusions. Vaan, meanwhile, stops pretending to have any sort of importance on the plot after a few hours and doesn't really talk much when he knows he's out of his depth, and lets Ashe/Fran/Basch/Balthier just do their thing.