Very well made. Your points about alignments, specifically evil, might upset some dnd guys, but are completely valid in my book.
I think that more than the evil characters themselves (you nailed their issues), the problem is the lack of meaningful interaction between them. It's like each one of them is living in his personal universe and it makes the goblin fortress feels like an mmorpg city, when each one of them is a different quest giver. I don't know how much of the good path you played, but although not much better, at least the druid grove has factions and infighting and druids acknowledge the tieflings' existence.
One point about the avenger archetype you alluded to but didn't say explicitly - paladins are kinda evil sometimes