My beta city is quite small and neglected, so I cannot actually playtest chapter 18. But based on the information given so far, I see a small but extremely long-lasting annoyance heading my way (and probably heading for other players too).
Problem:
I produce by clicking on a manufactory and pressing the shortcut key. 1 for standard and 3 for sentient by day; 2 for standard and 4 for sentient for the night.
With level 32, production options will change, and judging by the screenshots, T1 manus will change to: 1 for standard, 2 for sentient, 3 for ascended by day; 4 for standard, 5 for sentient and 6 for ascended for the night. Except for 3h standard, all keybinds will change and I will have to retrain my muscle memory for T1, and surely I will do some wrong productions on the way, mumbling a little curse each time.
In chapter 19, production options of T2 manus will change, and I will have to retrain again, involving more mumbling.
In chapter 20, production options of T3 manus will change, and I will have to retrain again, involving more cursing.
That is three chapters of annoying muscle memory retraining, even though it is really only one change.
Possible solutions:
A) Leave standard productions on top left and middle, sentient 3h in the top right, sentient 9h bottom left of the 6-production-layout. It would look less pretty than 3h=top and 9h=bottom, but keybinds stay the same, no need to retrain.
B) Rearrange the position of production options, but leave the keybinds as they are, so no need to retrain. This has the clear disadvantage that keybinds no longer correspond to the position on screen.
C) Do the rearranging of T2 and T3 with level 32 as well, and fill the ascended production options with a grey "Unlock technology" square. Will require a retraining, but retraining for all manufactories will be at the same time, it's over after chapter 18 and does not annoy for another year to come.
Please note that muscle memory retraining will be necessary for pure mouse users anyway due to the layout change to 6 options. While solutions A and B are great for keyboard users only, solution C would bring a relief for every player.
You may argue that we did have a transition of production options with the introduction of sentients and nobody complained about it being dragged out across three chapters. But - the layout did not change, and the keybinds did not change for any of those production options that survived through the change.