Hi Larry,
Okay, you find it sounds thin. What makes you think that the rack is going to sound any thicker? While it may a little, it won't be drastically different.
Here is my take on the Triton and the Trinity (which I own). The programs, on their own, sound great but a little on the thin side at times. However, when put into a mix (like a sequence), they sound great because each has its own space. I find it is best to combine some sounds from the Trinity with a JV-2080 or something similar. While the JV doesn't have the impact sounds, it has some good sounds and is much warmer. The punch and clarity of the Trinity offset by the warmth and thickness of the JV-2080 make a great combination IMHO.
Now, getting back to your question. If you are getting the rack for more expansion slots or because you don't need the keyboard, then that's fine. However, the same things you question now will still be in question after the rack. If you don't like the sound, I would suggest getting something else instead.
HTH,
Fernando
p.s. - also try combi mode sounds. They can really be quite powerful and thick if you want them to.