Considering that NRT development is at a standstill and there are some substantial issues that the developers will need to decide on before you see more development of either NRT or NRT-enabled NewGRFs, there's no point in trying to merge it into JGRPP because it's just going to lead to disappointment. It would require JGR himself to have to try to integrate it, and it would have to be a release separate from JGRPP. I can't imagine him being enthusiastic about trying to maintain two separate developments when the first one is already substantial.
If I were to merge it, it would not be in a separate development/patchpack.
It is pretty low on my list of priorities, but as and when the NRT development is sufficiently done I may look into it.