The steward saod there was unpleasantness and it wont be available yet. Why the hell not? I liberated Skyrim from the Imperials, and I need the house to become thane.

You need to become Thane to get the house. Have you done the 'help the people of Windhelm' quest?

trust me, you dont want it in its current condition. Do some quests in the city.

No. I assume I got to complete that first?

Yes, that's the method for every other city except Whiterun. Complete 'help people of [hold]' which should be given to you by the Jarl or someone connected to the Jarl. Then complete any 3 quests that are given in that hold.