I don't mind it being on high level or low level maps, but it can be discouraging when they occur on low density maps due to the low chance of cash shop drops. I've farmed some low density maps before and gotten 1 or 2 drops in the entire hour.
My first thought would be to take a look at the list of HH maps and get community input on if the map would need a density boost or not DURING HH only. For example, nif2, depths, and biospheres I would NOT want a drop boost on as they're dense and farmed often already.
My second though is it may be possible make the drop rate of cash shop items inversely proportional to the density of mobs on that map (not the number of mobs but the number of mobs per unit of walkable space). low density map = higher drop chance on the cash shop items.
I'd imagine this is a LOT of work and testing required and is not something that would be high on priority. There are a lot of maps that can show up on HH and each one would require testing to make sure they're balanced correctly.
The system in place now is a nice bonus and not a necessary one. I don't think I would want it to become "Farm HH or you lose out on a lot of stuff" but instead I like that it is "oh there is a great map on HH at the moment, let's farm there for an hour instead" it breaks up the grind for me rather than facilitating it.
