Well, think it through 1 step backwards
What was there in place of newly constructed T6 before chapter 15? It's not that T6 got plunked into an empty spot. Ranked players (and most everyone else) had to demolish something in order to build some settlement and ramp up sentient capability. More often than not, it was some T1/T2/T3 manus + maybe some Armories (some sacrificed expiring farms). After chapter was done, they more or less went to the same setup they had after Constructs, i.e. replacing excess sentients with regular production. So yes, they still keep their rankings as manu is replaced with manu, except they have way more regular goods production than sentients. This didn't change with completion of chapter 15. I don't claim seeing all the top cities, but this was the pattern that I observed in a few that I check periodically. As we were talking about excess of T6 post-Elvenar, I don't see evidence of that happening.
Duh...let me see, what was there...sheee...T3 factories. And let me think, what has been a bit of a problem for a while? Oh yes, a huge overabundance of T3 goods.
I used to have 6 T1, that became 5 and 1 T4, then 5 and 2 T4. For a while 4 and 3 T4 and now is 5 and 2 again. I MAY switch that to 6 and 1 again, but don't really need those T1 goods. Not to mention the utterly ridiculous demands for pop for maxing those factories. So I probably will cut down on that a bit.
I used to have 4 T2, that became 4 and 1 T5. Then 3 and 2 T5. When the chapter is done and I will probably go back to 4 and 1..
I used to have 5 T3. That became 4 and 1 T6. Then 3 and 2. Right now it is 2 T3 and 3 T6. Probably will become 3 and 2 after the reorganisation. Maybe 4 and 2, IF I can find the pop for it, but space will be freed up by moving yet more workshops into my inventory because their output is tripled and there is no good way to spend those supplies.
Either way it means more goods for which I have no real use either. I make mostly long runs, but still have about 7 mil of each of my regular non-boosted goods and about 2x that of each of my regular boosted goods, 3x on Dust actually.
Sentient goods however I will be needing to further upgrade my Timewarp and Simia (and probably the 2 for chapter 15 as well) so I will still need those factories anyway.
Armories? I have 3, but probably will cut it down to 2. Same amount of squares, just change of shape. But replacing one with 2 orcnests gives me MORE orcs on a smaller footprint AND without supplies. It will drastically reduce my trainingsize (especially with the SSS at high level) but I'll probably compensate that by starting to invest heavily in the Dwarven Bulwark, which will net me more free troops as well. Since I'll be needing fewer supplies here AND will need fewer workshops that pop can just as well be used to put up yet another factory (or max more T1/T4s)
So either people will put back the T3 factories (which I already mentioned in the post you reacted to, as T3 is so much more efficient for buying kps), or people like me will put back those and still keep some additional sentient goods factories going on to help others get the amounts of T6 goods that are needed in such huge quantities in this chapter and help them out by providing some extra of those.
So either way it is unbalanced again by having more of one type of good. And the overabundance of T3 already was a problem. Many people found the space to squeeze in an additional factory instead of replacing them, so that may be a lasting effect. Especially since the expansions in the techtree only could be unlocked after one had all the guestrace buildings up, and thus generally weren't used for those.
But it doesn't matter what choice one makes. The space will be used again and it will be mostly T3 manufactories, sentient or not. Unbalanced is the word that comes to mind, which will become worse and no doubt then it will suddenly have to be 'fixed'.