Played it a bit, fought with and against the positron forces in a few cruiser-flagship scale battles.
You're right in that the stats need some balancing - generally, the Positron forces feel a little too good for their price. That might be what you're aiming for if you thought the tri-tach weren't good enough, but I think they're just a shade too good for the cost right now.
That being said - I thought all of the support ships were going to be too tough - for example the Hauler class is pretty heavily armed for a freighter! (it also has a massive 800 cargo which I was unsure about, but I haven't really paid enough attention to cargo capacities to be sure yet)
That wasn't the case though, they went down without any trouble, never really did more than fire a couple of missiles that weren't a big threat, so perhaps I'm wrong about that. The Onna-Stick (don't like the name but not up to me
) seems like it fills a hole in light-freighter, though the 2-deck carrier does seem too small to actually have 2 in my opinion.
Generally I think their shields might need to be a bit less efficient - Positron ships are either fine, or dead, with not much in between, and even my Dronart carrier just absorbed a worrying amount of fire without cracking.