I find terraforming strategies to be a bit one-sided:
...
I suggest to improve ground-based facility to either:
Not require population to function, OR
Work better than a single terraforming module on a ship (like, 5 times more powerful).
The differences between a TFI and a module are:
TFI requires 250k workers.
TFI costs 20% more (600 vs 500).
TFI requires 5 times the tonnage to transport (125kt of cargo holds vs 25kt of module size).
TFI gets planetary/sector governor bonuses, module gets ship commander and NAC bonuses.
TFI must be built by factories. Modules can be built in factories or in shipyard.
TFI generates tax income.
As it stands, I never build TFI.
The only relative advantage is the tax income, but the long-run economic bottleneck is always population, and I would get the same tax income by using those workers in other installations.
If you remove the population requirement from TFIs, then I might actually use them.
To be worthwhile, I'd have to have a governor with a significant TF bonus, a large and long-term TF project, freighter capacity surplus to anticipated requirements for quite a while (perhaps after having completed a large migration effort), and enough fuel production that I don't mind spending five times the fuel to transport them (compared to moving the equivalent modules instead).
Honestly, I think the answer is to make the installation/module dynamic equivalent to that for mines/automines.
Make TFIs cost 250 (half the cost of a module), require 50k workers, and require 25kt cargo space.
That way modules offer the same economic tradeoff for installations that automines offer for mines (twice the cost in exchange for not needing workers), instead of being a much, much better deal like they are now.