I find it's just kind of a minor annoyance. I could be doing it wrong, but to get any kind of bonus from you it you have to go pretty deep into Harmony and get techs that aren't otherwise useful. So if you go anything but Harmony, miasma is just there. There's no bonuses to be had from it and at best you can make it a neutral tile modification, otherwise it's an annoyance. And as for the internal lore of the game, I feel like they could have done something that made miasma more 'special' that you could do things with it or it would have some impact on your game other than 'minus X hp per turn' or 'plus X hp per turn if Harmony player'. It just feels meh..... Thoughts?