"Those spikes on the front of the nacelle caps (and main sensor dish) could instead be sensors for detecting space conditions for the engines along the same lines of altitude and speed / temp sensors on an airplane."
I concur, given his aviatic background that's what Matt Jefferies probably had in mind (I have to add nevertheless, that he was still very aware that the Enterprise
is a spaceship
and accordingly added maritime elements. IMHO, this is one of things that made his creation so unique - there's such a fine balance between naval and aviatic components that it's impossible to pigeonhole the Enterprise
an airplane or a ship in space
"That is an interesting observation about the destroyed caps from "The Doomsday Machine" as their destruction didn't immediately indicate that the warp engines were destroyed."
This has been bugging me for over three decades making some sense out of the VFX shot from the episode. I should add that the idea that these caps might
be antimatter reactors would not have been possible, had you not presented solid evidence (IMHO) that there are at least three such reactors aboard the Enterprise
With the one in the engineering hull still intact, it makes sense that Scotty first checked the engines, as one reactor probably still could have provided warp power. Wasburn's report only indicates that the antimatter in the warp nacelles had been rendered inert (so the one in the engineering hull may have still been working unless fusion power was sufficient to charge up the Constellation's