I've spoken about this in the update thread but I can talk about it here aswell.
We only really nerfed floors 4 and 5 and even then only by a small amount. We'll continue to review it as time goes on.
I absolutely want Sepulchre to be the best way to train agility if you're good enough to do it however the gap between looting and not looting is pretty large, perhaps bigger than I'd like.
You should still be able to get slightly better rates while looting chests than rooftops but if you want to get much better rates you shouldn't be looting. If looting was significantly better than rooftops then not looting would be absolutely ridiculous, that's what this nerf was attempting to address.
I'm considering adding token amounts of agility xp to crossing bridges and going through portals similar to grappling to help off-set the difference in upcoming weeks if I think it needs it.