I second this unfortunate observation!
Worse: "Nova remnants" are identical to the original star, so, other than the name and the fact that it won't "evolve" anymore, it's the same star, unchanged. Very frustrating.
I've converted a couple of "nova remnants" into some nice neutron stars, though. Basically, very tiny, very dense and very hot. I've got one in blue white and one in ultra violet (I think). Let me know if you'd be interested in one of these more legitimate "nova remnants"--which should be SUPERnova remnants. A nova remnant, if memory serves correctly, is what you get (if anything) after white dwarfs explode due to accretion of hydrogen from a neighboring star. Sadly, UBox2 does not (yet!) simulate that.