At the moment, it's easy to drop into a hotspot and find nothing for half an hour. This gets really old, really fast.
What about halving the yield but doubling the number of core rocks to keep it commensurate. At least that way, you'd get the feeling that you were actually getting somewhere.
If it's easy for you to spend 30 mins looking for a core, there's something you're missing. Color, shape, double ping ( color )?
While there are times that I spend 15 minutes looking for another, those are the exception, most of the time it's only a few minutes between. Sometimes I find 'clusters' where 3 or 4 rocks are within a few km of each other, spot the next one as Im leaving the dust cloud of the last.
I haven't found any need to travel outside of the bubble, usually spending about 2.5 hours to fill 128 cargo. That's roughly 9 or 10 cores, about 15 mins per on avg. That seems like a lot! BUT, most of the total time spent per core is just exploding, blasting and collecting the bits.
Not only would I not like less yield per rock, but having to explode more rocks would mean possibly having to change loadouts for more ammo etc.
Also, because setting charges and blasting surface deposits does take time, overall you might not be saving as much time as you would think.
The system as it stands makes 100m per hour possible...
