It's about ultra terraformers. They can terraform the same hexes as the two first terraformers you unlock in the game. We will call these hexes as "tier 1 hexes" here for the sake of simplicity, as there are other, lower quality hexes, that require better terraformers. But that's not the problem; the problem is that by the time I unlock them, I might have used other advanced terraformers to terraform those tier 1 hexes. That's because most people will simply use any terraformer to unlock any hex, regardless of its quality. This way, I could accidentaly use, say, a biosphere (which can terraform anything) or any other advanced terraformers on a tier 1 hex, and therefore, in late game, the ultra terraformer would be useless because there would be no hexes left that it can terraform.
To bypass this, I have been avoiding using any terraformer until I unlock the ultra terraformers. This way, I will use them first, and only apply the more advanced terraformers to the lower quality hexes that can only be terraformed by such. But it simply seems awkward for me to wait so long to use them.
So how do we fix this? It is simple: show us the "quality" of each hex that can be terraformed. This way, we will only use the advanced terraformers on the hexes that can only be terraformed by them, and save the tier 1 hexes for the ultra terraformers. Simple as that.
And sorry for the extreme repetitiveness of the words terraformer, I simply couldn't find a way to get around it.