The Maine was to become the US-answer to european monstrosities like H44- and Superb-classes. Once it was clear, the Yamato-class would outtake any existing battleship but the planned ultraBBs, the US Navy went for her members of the 1st class fighting vessels.
The planned 20"-gun was mainly a simply enlarged 16"/50 Mk. 7-gun, the goal was to deliver enough punch to counter anything existing or planned. Further the ship should be fast.
The Design 1 was much like the late CC-1 (Lexington) design three time pumped up to 115.000 tons empty and stretched to a ridiculous 401m length. The stern still had four shafts and two rudders, but all somehow oversized.
The 12 20"-guns where installed in four triple-turrets. Also unusual was the amount of 5"-turrets. Eleven Mk.28 turrets per side was seen as a need to protect the big vessel against air raids and the ship was expected to run without any escort shield sometimes. So that much aa and directors were planned.
The Design 1 would have been the lightest of the ultraBBs. But also the fastest one. The hull was very sleek, it was more something like a ultraBC, what is not really correct, due to the fact she still would have outtaken any smaller battleship.
The battlecruiserish look was the reason the design was rejected.
In that case I have two things:
1.) A reduction of your 5-inch armament by a quarter or third would
still result in a devastating AA/secondary battery. And upon second look your other AA armaments, particularly 40mm's, are if anything woefully underrepresented for a ship facing potential self-escort. And that kinda brings me to:
2.) If this is going to be a new design anyway you might as well make it a true clean-sheet. I'd start with looking at how to improve your AA-arcs especially with those funnels, and it'd probably use a tower structure closer to Montana.