I know it does not matter at this point, but I would really really rather not see a USB charger internally.
My primary use will be an emergency room light. With possible walking around as a flashlight. But I have a TK75 for that, with a spare set of charged batteries and 2 tube extensions. If the Q8 was used heavily for a while on a fairly bright range, as an every day carry, I believe I would prefer a second (or more) set of charged batteries rather than finding a USB charger and needing to leave the light sit there until it was charged. A 6A charger would be only (if all was perfectly balanced for state of charge and internal resistance) 1.5A for 4P. Getting the light to the charger, letting it sit til full, seems like it could cause an inconvenient time to full charge. You could use a standby set of batteries or take them out to recharge. But then you have incurred additional cost for the USB circuitry and any issues from trying to get them to fit.
If battery configuration has the 4P, 2P2S, and 4S configurations available, charging would be a bit more complicated. I am also guessing that unbalanced charge levels could be an issue.
And waterproofing an indicator and USB port. My experience with some of the available cover/plug devices has seen a relatively limited lifetime for the little rubber hinge. When that goes can you get in there easily to install a new one (and get one in the first place).
And wireless charging can be a serious challenge in an all metal device.