I'm opposed to fully removing immunity to gravity thing. However, I would love to see it become much, much more rare. And as Hearteater suggested, some of the units that currently have it ("mid-tier" to golem tier stuff and the Spire starship) I guess could get a partial immunity to it (the magnitude of which is dependent on the teir, so golems would get more resistance than Spire starships, for example). Only epicly huge stuff, like the Super-dreadnought and the Mothership should get full immunity. (H/Ks probably should not, given that they are like raid starships in terms of how the AI uses them, except much more scary even without FF immunity. H/Ks could probably use that partial immunity though)