Again, I disagree completely. When you conquer a colony of a race you don't own a colony of and you decide to migrate the colony, you also decided that you do not want to build any of their units, at least not before you conquer another town of that race. Still, you get the whole racial military tree - the only racial researches you don't get are the doctrines, which are part of the social tech tree. And the whole web of strategic and tactical operations plus mods not only is too much, it also doesn't make a lot of sense, considering a) the damage channel techs would be "there for the taking" just as well and b) why do you get access to the whole tech tree, just because you conquer some colony (keep in mind, it might be an independent one)?
Why not?
Again: We are rediscovering Star Union Era technology. Very few things in the game are original research in any way, shape or form. Only the quest researches have any shoot at being called original research.
Most of the Mods do not mater. Because they are specific to teh damage channels the species has. And thus the units it has.
The unit unlocks do not mater, as again: You do not have the colonies to actually build them.
Wich leaves the Operations. Wich are also often designed to work with the Damage Channels of the species.
Let us take the Amazon Tree for eample:
The Topline is 90% Units and Hero Vehicles. The hero vehicles do get Laser damage channel (for wich you propably lack mods), but beyond that the line is utterly worthless.
Aquatic Subtechs? Again worthless, as you lack the Cities to use it.
Protective Grounding:
A Stagger Resistance Mod and a Heal/Regeneration/immobilize combination. Wich are situational at best. Anyone that needs Stagger resistance as a gameplay strategy already got it. And the rest do not really need it.
Primal Control:
The PAA is potentially usefull, due to the "can not be flanked" rule. Certainly one of the stronger Detection mods.
AIC does not mater if you do not got any mounted, Animal or Kir'Ko units.
Primal Override looses a lot of the powers if you lack sleep/entangle. Wich again, are abilities on the Amazon units. And it is mostly about getting Animals for the AIC anyway.
Forest Geensis:
Rapid Reforestation gives you nearly nothing. All the racial abilities for forrests are on the Amazon Units or Social Tree.
Entangling Overgrowth: Usefull
Regenerative Bio Resonsance:
Regenerative Bio Regulator: Regeneration is usefull, but the cost is propably a bit to high to spam on T1 units. It also does not work on any Mechanical Unit - wich are common on the high tiers. The only ones with use are Kirko (wich have their own variant of Regen) and Assembly.
Nourishing Field Pylon: Okay, usefull
Amplified Bio Resonance:
Crushing Roots: Typecast mod for the Arborean, but it can be used on growth units too I guess
AF Pylon: Potentially usefull
You are now 21.7k Reserach into the Amazon Tree. Most of the stuff is useless without the units they are designed to support.
You could have invested those same resoruces into your own Racial or Secret Tech tree and propably gotten way more pwoerfull stuff out of it.