Ascension is coming back in 6.19 and as of this posting it should be enabled for testing. We don't have any big changes for the mode this round so there's nothing to specifically focus on. As always let us know if you see any bugs/feedback and have fun playing!
Some known issues we're working on fixes for:
* Casting Maiden of the Mist (R) in the fountain will cause Yorick to lose access to his ulti for the duration of the game (as the maiden and ghouls will be stuck on the fountain)
* Casting Maiden of the Mist (R) on a teleport platform will cause the Maiden and ghoul AI to act incorrectly (they basically get stuck trying to use the "lane" for Crystal Scar.