Regardless, as paladins remain our only unit that are flexible with sanctic powers, you'd still be taking at least 1 x 5 of them. I'm probably agreeing with Corvus on this one, but that Purifying flame being now 9" (IIRC) is incentivising to take at least 1 x 10 Purifiers (on top of their +1 to cast). IIRC, they also get teleport strike, which means you could just throw them in deep-strike for no cost. Then for full fluff effect you could even bring a Land Raider and throw sanctuary on it. Having them inside with a 2+ save, and a 4+ invuln LR, puts them in the same category as NDKs in terms of survivability.
There seem to be two archetypes with the new GK lists - full MSU, or NDK. I'm thinking competitively, the MSU one will be better, however I'm uncertain to the potential of a 4+ NDK. I played NDK's with early 9th with 3+ invulns through Heed the Prognosticars, and Sanctuary, and they stuck around, not sure how 4+ invulns will go through. That being said, they are exactly the same as Leviathans for SM just without smoke screen and one less wound. And those stuck around pretty long in my DA games. So take that as you will.
Currently my default list looks like this (no powers selected because BS hasn't updated yet, and unsure about brotherhoods - eyeing the second one for rapiers though):
Love your list, however at the moment I just can't bring myself to using any Terminator squads due to cost, seems super prohibitive. I am leaning more into strike's than you currently in a mass MCU PAGK horde.
Going back to your comment about taking Purifiers and deep-striking them. I am currently considering a 5-man and 10-man Purifier squad with 4 incinerators. Then combat squad the 10-man and deep-strike the 4 incinerators in to hopefully cause some damage to the lesser save troops units we are seeing more and more of. Then the other two 5-man purifiers are heading up in a Rhino hoping for a second turn double Purifying Flame cast.