I'm having a similar problem except after getting the "must help definding..." message I'm unable to enter the city, I just keep getting the message over and over if I try to open the gates. Generial Tullius and the Imperial Guards are just standing animated outside of the gate and if I try to talk to Tellius he just says generic lines about killing Stormcloaks and spies everywhere. The location itself still hasn't reappeared as a fast travel point on my map and the exterior of the city is still in ruins. The inside looks normal other than Ulfric and Galmar being dead.
Several in-game months have gone by. I've gone to Solstheim to complete quest, I've traveled to all of the other major cities, completed other questlines, etc. and nothing brings it back to normal. I've used the console to travel inside but once I walk out I'm stuck again. The new jarl hasn't taken over, the Jarl from several other cities are pacing in a room upstairs and react negatively when I've talked to them. I've try recycleactor on Tellius, I've tried marking him mortal, killing him, and resurrecting him, I've try setting the stage of the last civil war quest earlier on in hopes of finishing the quest again and resetting the game, and nothing seems to work.
I can live my life without being about to buy Hjerim (no new management to sell me the house) but I'd still like to be able to come and go as I please. If anyone has an suggestions I'm all for it, and loading a previous save is not an option considering I've put dozens of hours in since completing the quest. I'm using a few mods but nothing that affects story/location/quests, just ars metallica, CBBE, and pick up books without reading.