Usually I'm no big fan of retcon activity and if you feel implementing sets from ENT into TOS constitutes such retcon activity, I'm the last one to object (although the corridor walls in ENT could simply be replaced with those original TOS energizers / reactors as the production crew and Matt Jefferies would have recycled existing components for new sets).
Where I beg to differ is your criticism of "new" Trek lingo for TOS lingo. I think it's safe to assume that in TOS, too, it's some kind of "plasma" that runs through the tubes to the warp nacelles, though it has not been explicitly mentioned in TOS. With your kind of reasoning, "nuclear fusion" would be a no-no, too, as it had never been mentioned in TOS (but since cracked lithium is a vital component of a nuclear fusion reactor, we can safely assume that Delta Vega mining station produces materials essential for nuclear fusion).
Sorry, it's a conclusion I arrived after having finshed the engineering deck plans I've been working during the past weeks (I felt compelled to add the ENT sets). I would like to publish these in a separate thread (as recommended by Peter Chung) but I'm not yet allowed to post attachements. I can probably PM them, but of course won't do so uninvited.
The corridor with the horizontal pipes was quite a challenge. According to the location of the Jefferies Tube where Archer and company ascent they would be arriving near the lower starboard plasma conduit of the "cathedral". These four square lights probably belong to the plasma conduit (similar to the square lights on the overhead conduit in the cathedral) and could explain the strange flash effect in "The Paradise Syndrome" (there HAS to be a hidden light source).
Archer's people close in on the Gorn's communicator counter-clockwise while Archer moves further to the stern, hoping the Gorn will retreat clockwise (below and around the cathedral) so he can "receive" him. The two "energizer" corridors are right below and behind the TOS engine room. The two branches of the Y-shaped corridors face aft. Later in that episode the central hub connecting these corridors features the primary electro-plasma relay which, IMHO, connects to the matter-antimatter reaction chamber above in a similar fashion (and design) as the extendable dilithium crystal assembly in the TOS engine room.
As the ENT sets helped me to fill a blank spot in my deck plan drafts, did not contradict anything seen on TOS and featured some design elements very faithful to the original series (energizer walls, EPS relay assembly) I found these to be a most welcome addition to add flavor and diversity to Kirk's television Enterprise.