[Loser]

This sounds like a very fun idea.

It would not be too difficult to make certain techs 'savage tradable': all you have to do is pick out certain techs and not make them require the non-Primitive racial tech. You could even have zero-cost sub-techs that yield below-par components, facilities, ship sizes, or Intel Projects that have certain 'real' techs as prerequisites, so that when a race gets Intel I they can then research Primitive Intel I for no cost and trade it to the Primitives, who can then do whatever they want with it.

I think the Primitives should have the capacity to produce some small amounts of Rads at some point, just so they can support a ship given to them by a player. "You gave a baseship to the Ewoks? Do you know what they're going to do with that thing?!"

The Primitives should have superior infantry and, if possible, militia to start. This is both to keep them from being easy prey (human vs. AI, after all), and to account for the fact that they probably still kill their own food.

Since the Primitives are not only AI, but dumbed-down and limited AI, plaguing them out of existence would be too easy. I feel that these races should have plague resistance, of some sort, from the get go. This could be said to reflect their hardier, already survival-of-the-fittest lifestyle.

There could be a non-Primitive tech tree, let's call it Uplift for now, that specializes in techs to be traded to Primitives: Resupply, Troops and Infantry, Anti-Plague, and Repair ("Now listen here, little-bear-people. This is a Wrench. I know it looks kinda like a hammer, but you're gonna hafta trust me on this one...")

With these techs requiring a non-Only-only tech to research, but not non-Primitive only themselves, the Primitives could not get them on their own, but could get trade for them or even steal them. These techs would be better than the ones available to the Primitives, but not as good as non-Only-only techs.

If you give another player a transport with Weapon Platforms on it, the Weapon Platforms are his too, are they not? That would be fun. ("How in the blue blazes did Ewoks get CSM V??!" "Look at the hull of that Weapon Platform, sir. Those Weapon Platforms are Narn.")

I haven't modded, but the way I understand it, this should all be possible. All except the Neutrals part... I was under the impression you couldn't mod Neutrals.