The protagonist topic is quite difficult, I haven't figured that out yet by far.
I'd say that, if you choose the story to revolve around them, they need to:
- Not be actively annoying to read/watch.
- Be interesting enough that you care at least to some extent about them.
- Have connections with most of the cast, have the story be more interesting because they're there.
The first one is a requirement to be a 5/10 protagonist, but the second and third points are what this topic is actually about.
Regarding the second point: The mc can not be everyone's favourite character, and that's completely fine! They can't be and you shouldn't try to get everyone to like them, they just need to be interesting, have flaws but also good traits that make them complex and interesting to follow, grow through the story, etc. Many people covered this super well above already - and also why consequences are important, that'll add a lot of interest to the story and the character's development.
Now, the last point is one I really like to think about. The main character is the one we know the most about, we see how they interact with the other characters, how they affect the rest of the cast's life... I think it's important for a protagonist to do that. They're the core of the story, they're what ties it together, so it just makes sense that they have interesting, deep connections with most if not all the cast.
The story will end the moment the main character's journey does, so it's cool to see how all the characters' lifes have changed since the moment they met them up until the story is done, how the mc's doings have affected them.
All the characters can develop because of other reasons that aren't the mc's doings, of course, but the mc's actions should, at least, be a small influence in that development (if possible, of course. If those characters lived in the past or whatever then there's nothing to do there).
I'll be keeping an aye on the thread to see if there's some more advice on the topic <3 (and not saying anything about the lgbt+ overrated topics because I really can't think of anything relevant enough to add lmao)