Best Alternate Timeline Excelsior Refit i have seen so far.

BUT ( yes, i am a critic ):

JJverse attempts to roundwash EVERY.DAMN.STRUCTURE. that kept Starfleet Ship designs of decades in balance between beautiful, impressive, and grave.

Starfleet is the flying guarantee of stability under all circumstances, also by design.

Even the petite Oberth felt sophisticated and grown up from every angle, convincingly crafted by the practical wisdom of engineers. Form follows function was the mantra.

So when you are clearly able to rework and complement the good ol´Excelsior ( yes your draft is well made )...

- Please dont use the "all new" curved nacelle pylons, just to implement the new timeline with sheer force. They just don´t work, even if they are canon now.

They pressure any form of ship into a static speed impression of a straight going, hyper fast rocket, like a F104 Starfighter.

Starfleet ships always felt like big sailors, being able to swing around in wide curves, so they needed ( and had ) good proportions in the horizontal level.

These Pylons are a break in the lines, a break in the balance, in the over all form of it. They take all the maneuvrability out of the Ship´s shape.

The Rest is great, i trust in your ability to figure out something that deems the original, with your OWN note.

Not with what´s given.