SWTOR nowadays is pretty damned fine because they changed it up and WOW Classic TBC Gold made it so just performing the story missions about the planets was sufficient, and the stories are good, although some expansions are certainly better than others. I'm quite happy to return to SWTOR for a couple weeks every once in a while.
I know that it's a repeating quest. I understand those NPCs Aren't really important and all
If you want to experience a game that has a good story you can casual to your hearth's content without sacrificing the basic MMORPG mechanisms (that I think ESO lacks), I suggest you attempt FFXIV. Best of all, unlike WoW, FFXIV keeps all dungeons and raids level synced and has them on a roulette, meaning you can always find players to run them more or less how they were at launch.
Private stories make me want to perform all of the races and have fun together, get to know their stories. I can willy-nilly across the map and there is a quest and someone to speak to everywhere. I realised I loved GW2 when a caravan pursuit was about to start and a priest came out and cheap WOW TBC Gold gave a speech, blessing the journey along with the caravan NPC was commenting under their breath