What you describe seems to make the TMP and TNG layouts rather equal, with a compact reactor and its power conduits - whereas the TMP layout in Probert's concept was reputed (yeah, citation needed, but Probert's website isn't working too well) to feature power generation all along the length of the piping, an idea Sternbach perpetuated for the VOY core. But none of the theories ever got onscreen verification or even much in the way of support.
Personally, I favor this piping being mere power leads in TMP, just like the same set piece supposedly serves as power leads in TNG. And everything we see could fit on the same curve in this particular sense: STXI shows the cluttered innards of a mid-23rd century starship engine room, TOS shows the sterile control rooms of the same, TMP again returns to the rarely accessed innards where people work in heavy protective gear, and TNG finally advances the tech so that vanity covers hide most of the clutter but the main machinery is now safe enough to be directly exposed to the control room. The actual machinery is pretty much the same all the time, though: reactors looking like big boilers, power leads looking like neon tubes, and dilithium inserted into the reactor somehow. But a row of huge beer tanks becomes a single compostor-sized thing between STXI and TNG.