I for one do not equate eyecandy with realism. And I find the long loading times, mod fragility, AI side effects, inability to easily swap modules in and out with JSGME game killers.
Compared to that TMO is small, installs in seconds with JSGME, plays well with some others, doesn't slow SH4 down and packs a huge gameplay punch. It has eyecandy that you will see every day. It does NOT have eyecandy you might see once in a career.
Like I said in a post above, TMO and RFB were consciously NOT designed to replicate GWX. They were made by people who had what they considered better ideas.
Calling any of them realistic is truly laughable. There is NOTHING realistic about GWX, RFB or TMO. You can't get wet, you never buy fuel, machinery never breaks, your sonar man works for the IJN, there are no wolfpacks, you cannot talk to Admiral Donitz, you cannot move torpedoes from the bow torpedo room to the aft torpedo room or vice versa, nobody smells and you can't die. I haven't even scratched half a percent of the surface. Nobody can call either sub sim in any of its mod configurations more than a couple percent realistic. You're beating a dead horse.