I mean let's follow this logic. Why does Hussie hate Tavros? It's not that all this time went into crafting a character, pulling him out of the kiln, and then going "oh this guy sucks." Tavros sucks by design.

If Tavros only had one personality trait, it would be indecision. He refuses to pull the trigger on anything and subsequently has to be dragged through most of the story. And the few times Tavros does manage to take initiative, any kind of negative consequence gets him to quit. Ironically enough it's Vriska who believes in Tavros the most; up until killing him.

What does "Tavros but the story doesn't ruin him" look like? For starters, pretty similar to what other characters are already doing. We could compare Tavros to John, who also has to be pushed into adventuring but is headstrong and less annoying. Or Karkat, who isn't a powerhouse either, except Karkat is willing to have difficult conversations and get his hands dirty. Hell, let's try comparing Tavros to Vriska. Tavros killing Grandpa is tangential to Vriska creating Bec. Except Vriska tries to take responsibility for her misdeeds instead of apologizing and running away (See also: why (Vriska) sucks).

Does Homestuck have too many characters? It certainly has too many characters for all of them to be cool people who get stuff done.