While Star Trek has had design inconsistencies throught the movies, it has always kind of been in some sort of time progression to kind of explain this. Also, the characters actors remained the same until the JJ reboot. He opened pandoras box in that departement and it was for milking a franchise that should have stayed dead, just like Hollywood is used to doing nowadays. SW VIII, despite the silly plot, did alot better in that departement.
As for STD: There are several things that bother me about their design choice (my personal opinion):
1. TOS, to me, is the wild west age of Trek. Just leave it at that. Its 60ies style "cowboy diplomatics", cheesy, somewhat silly but still progressive for its time. Recasting the actors and using a more modern design, will make for different stories, athmosphere and eventually universe. At least the way they seem to be doing this now. To me, STD is a reboot of the series. Different actors, different design etc. I dont care if they say its the same timeline. It isnt. Its basically a new timeline, a retelling of the same timeline with different actors and different design is nothing else than a reboot. A timeline is tied to a specific design progression, fashion, faces etc. Ok, lets call it a soft reboot. (Or whatever)
2. If we would stay true to Roddenberrys idea of a very very streamlined design of ship interior, then this new Trek does certainly not fit in there very well. At least not from what we see in the trailer. (This could change of course) Of course the limitations of the 60ies FX hd their role in the streamlined design of the 1701. But look at TNG: Despite the 90ies camp, the Okudagrams seem to fit very nicely in the modern day still but were due to the demand of a very streamlined and user-friendly design. The esthetics of Trek should be in line with the kindo of utopian future Trek wants to be in.
3. To have a continuity between ENT and TOS, but setting it 10y before TOS, made for a ENTxTOS kind of design? Thats just stupid. Its like making a movie about the early 20th century, but with ties to 1850ies clothes. pls.
To be in the same timeline:
Yes, I understand the need to adapt the Series to current technological advances, but they could have done it in a different time. Setting it, f.e. in between TOS and TNG, somewhere around after 1701-C, could have given them the opportunity for different more modern designs. Setting it after TNG even more. Just use the Okudagram basic design and add to it more modern features and its ok. There are many choices possible for uniforms between the red ones and the pajamas from TNG.
But I understand the convoluted universe and stories, make this difficult to stay in canon.
Or just make a total reboot:
Forget about Trek lore completely and hard reboot the series. Just use some of the same Aliens and the utopian vision, some of the tech etc. but different actors, characters and stories. Give the fans some service here and there and be good. Just like BSG. I mean, a series about a starship exploring the unknown universe: The opportunities are endless. Trek was kind of dead after the more or less failed TNG movies anyway.
Finally, of course they do what they want, and I'll watch it and will probably enjoy it.