For some reason, the last half a dozen replies got deleted or hidden and I can no longer see them. I dunno' if it's because of a forum 'glitch' or side effect of maintenance. Oh well.
To repeat the most recent thing I said, it turns out Infiltrators cannot copy T3 units ever as Tom said in the first Invasions stream. Hope your opponent isn't able to bring fully-T3 stacks, though if the game does reach that point, there's probably other much worse things to worry about than being able to copy their units.
Also, I'll admit it's still useful to copy units like the PUG, Hidden, Transcendent and Biomancer. A pity that you won't be able to properly copy the enemies' all-beefed-up Jetpack Troopers and stagger resistant Lancers and etc., which will still be a bit of a problem in the late game, especially if you end up facing an opponent that only builds those kinds of stacks. In which case, I'll be more glad that I built Deadeyes and Raiders over Infiltrators.
Anyways, in other news, it turns out I was wrong about a previous speculation that the Shakarn naval unit will be scrapped or absent despite appearing in the concept art. As they do still have one, the 'Seeker'. Probably no T3 ship though, much like the Syndicate.