you don't even have to consider trading and holocrons
if you just look at the concentrations on the map
Ore crystals come in patches of 250 each sqare..
Nova crystals are 800 per square
so say you have an Ore patch of 4 squares, thats only 1000 ore
compared to the 2400 you would get from a Nova patch of 4 squares.
And Nova is MUCH more common in massive patches of 10-12 squares, Ore's highest is normally about 9 squares, maybe more sometimes, but it is commonly found in groups of 2-3 squares