No doubt SNK/Playmore can be commended for supporting that hardware platform for a really long time.
But certainly the NGCD was a budget system with limited RAM. It couldn't play the more complex games without load times. No arguments here.
It is what it is, and a neat addition to the collection. If you dislike the load times, an old XBOX with the emulator and ISO rips of your games completely solves that problem in modern times.