I just started to wonder: Why would Talos, as Wulf, give the Nerevarine his blessing before he goes on his journey to destroy the heart of Lorkhan.
Wasn't the Heart of Lorkhan one of the things that kept up the barrier between Mundus and Oblivion?

I thought it was quite contradicting, but since most people here have more knowledge about it, I thought to ask you.

Dagoth Ur was bound to enslave, if not, destroy Nirn, so Wulf had to aid the Nerevarine as the Nerevarine prophecy is part of Alduin's prophecy. Why he did it specifically, we do not know but IMO maybe he was helping him because by "tradition" Alduin is supposed to "swallow the world", and was basically telling Dagoth Ur to back off.

1st) He was protecting mankind from Dagoth Ur
2nd) He was freeing his heart

In Wulf's own words:
"The Emperor is getting old. Don't know how much longer he'll hang on. So is the whole Empire, for that matter. Getting old, that is. The Emperor and the legions have held the Empire together for hundreds of years. It's been a good thing, by and large. But maybe it's time for a change. Time for something young and new. What? No idea. Because I'm old. Old dog doesn't get new ideas. But maybe young folks like you should try some new ideas. I don't know. Could be messy. But change is never pretty."

He wanted to shake things up, to end the/his aging Empire and let someone new come in. The shut-down of Red Tower and the weakening of the barriers helped do just that. If Red-Tower didn't go down and Uriel was still assassinated, the Ob Crisis wouldn't have happened at the level it did, and they might've been able to get Martin on the throne to continue the Septim Dynasty.

I think it was less about shaking things up, and more about knowing it was inevitable.