I see the turntable more as a convenience than a necessity, plus it lines the shuttle up nicely with the launch/landing rails.
I kinda see where Timo is going with his thinking. It looks like he is basing it on "The Final Frontier" where there is a circular "turntable" like structure in the middle of the flight deck, just ahead of the parked shuttles. (And the parked shuttles are just ahead of the two elevators with sliding doors.)
Looking back to TMP, it's hard to tell if a circular area was there on that flight deck.
Although we can make out a rectangular area in the middle with lines in the middle leading out to the open shuttlebay doors (like the launch rails).
It's worth trying that idea out - although it will lead to a longer flight deck since the elevators at the end will add length. I do like the combined elevator and turntable though as it seems simple and retro compared to the elevators seen in TMP.
As to the differences between TOS and TOS-R, I put them in different continuities since the VFX is pretty different. TOS-R is more likely to come from the TNG+VOY+ENT-universe while TOS is it's own. For me it keeps the confusion down and simplicity up