The heat of the batteries versus the emitters is a question I would ask. If you over-drive less emitters, you're looking at more wattage and more battery heat,, imho I believe most batteries are damaged by heat before anything else, this is why high drains exist. Imr high drain cells survive and maintain best performance where high capacity li-ion cells get damaged and reduce their capacity, in my case, in one year of use, about 100 charges my LG HG2 batteries (and those are usually good with high drain) got damaged from two or three times I pushed the limits of the light they are isolated to, my tk75. In this case, my batteries have lost over 25% of their capacity. Typically that wouldn't happen for 500 charges or more.
The stock x80 is putting more stress at the head than the batteries, by not even using the full potential of batteries, the critical limits to this are important. It means as it stands you can probably use any type of 18650 you want, without much hesitation, because their internal resistance is more easy to handle.
This of what I'm saying, if you are right. If you're wrong, and extra leds don't actually mean more heat, but perhaps less since they are so close to the edge of the head, then batteries may be irrelevant, and the point is still finally given value: the x80 was created naturally and deserves additional respect for their multiple LED design.
I think separating the leds makes them cool faster, not slower. Like a xhp50 being split from 4 together to 4 apart.