I don't mind Varus being 66.66% gay
In fact, I think his new lore, as a standalone, is amazing.
Buuuut..
The new lore is a detriment to the original Varus' revenge trope. Previously, Varus was explicitly a warden of the pit of Pallas, so he KNEW what evil was lurking beneath. In the new lore, it is not clear if Valmar is aware of the consequences of his actions: he hopes Kai will be healed and everything will be fine; he's not signing a pact with a great evil that he knows will consume him. The intent is missing. This takes away a lot from the story. There is no self sacrifice.
What was amazing about Varus' previous lore is that you had this warrior that devoted his life to the protection of a great evil, but also loved his wife and child. He was torn between his duty and his family, (this aspect is nowhere to be found in the new lore), and ultimately decided to leave his wife and child to die slaughtered by the noxians. And for nothing: with his city falling under the siege of the invaders, the power of the pit of Pallas was doomed to fall in noxian hands. Grief and revenge moved him to steal that same power he sworn to protect, in order to get revenge.
In the new lore, everything happens so fast there's no time to meditate such a dramatic decision. Kai is dying faster than a racecar and Kalmar is compelled to save him. Valmar doesn't actually lose Kai. He's not consumed by hate and lust of revenge to the point he's willing to sacrifice everything.
TLDR: There is no duty vs family dichotomy. There is no loss. Everything happens fast, and in order to save Kai. There is no intent in releasing the evil form the pit to exact revenge. There is no Varus.