Aesthetically, the whole design is something you would see during the Dominion War, like you mentioned, and not something you would see pre-TOS. Nice design, just a bit historically inaccurate in the Star Trek universe, IMO.
Asthetically, it's ten years before Kirk, because the IP owner says it is. I'm sorry, but you have to understand-the owner gets to call the shots with this kind of thing, and Word of God from the owner trumps speculation, logical evolution, or in-universe sense. (it's why I no longer consider myself a "Fan" of Star Trek on the whole now.)
It's very simple, really-they did a retcon on the universe, but state it's not a retcon, therefore, it's by definition not a retcon, and whatever changes they made, are no longer canon. this is kind of the purpose of Prequels and reboots.