So I've killed Alduin and have returned to skyrim, arrived at the top of the world, talked to partunax, and now what?
Haven't seen Delphine since we where in skyward temple. I returned there and saw that the place has been fixed with tables etc. But no Delphine or Esbjern, not there and not in Riverwood.
Had the impression you where forced to choose to kill parthunax and rebuild the blades but all quests so far is closed and have no directives where to now? is the main quest over just like that?

Haha they were problably on that balcony, just outside sky temple, they like to go talk with eachother there.

And yes they force you to kill parthunax, something you can just disagree to do, and go your way.

Have to check that balcony then ^^

You are not forced to kill Paarthurnax to do the MQ

I didn't. There's a significant portion of the MQ after the battle on top of the mountain. I feel the Blades can stuff it and I would have killed Delphine and Esbern for being two-faced if I could have. My main character never spoke to them again