Right. Basically all the battleships share the same hull pieces, and the cruisers share the same ones too. The only real variation is in the escorts.
If you want, I can pull out the unassembled chaos cruisers I have so you can see the second recess, but there's not much to see, just more of the same.
Personally I'd have gone with what you had, but added detailing inside and out. For detailing inside, some of the work I did is suitable, but as I'm working at a much smaller scale, there's so much more you can do.
If I could have, I'd have used references from modern military jet engines, and done a ring or two, like the burner/ignition rings.
Perhaps some reference could also be taken from the Sulaco engines?
(More detail shots of this one available, just need some digging. They're from a guy making the Sulaco out of paper, from scratch, as papercraft)
One thing that might also be worth considering is going back to the engine pattern you had, then removing the centre engine, and adding two larger ones arranged vertically, breaching the top and bottom. It might help break the monotonous shape, but it could ruin the aesthetic if it's specifically the shape you're after.