Greetings!
A few quick suggestions and comments:
- I think the fleet restrictions are generally needless. Availability of battleships, good. Mandating them? Not good.
- Demiurg escorts. Flip the RT Xenos Escort around and use the Defence Monitor Hull with a few bits clipped off and you have two perfectly sensible looking Demiurg escorts. One is a slightly bulkier one, one is a much smaller and more skeletal one. In my Demiurg list I denote them Rampart and Buttress classes.
- There's a few options for the Cutting Beam. Personally, after years of considering it and examining bits, I see very little reason to think that it shouldn't simply be a short ranged Bombardment Cannon or Lance. I favour the BC interpretation because it adds excellent critical hit opportunities, but requires a bit of odd rationalisation for effectiveness versus ordnance. I don't mind this because it makes it much simpler and 'neater'.
- There is still a trouble with the Castellan in which it is conflicted. This runs parallel to the problem with the Hellebore for the Eldar. That is: use of special orders. With a strong Torpedo/Missile component, you lose effectiveness mightily without reloading ordnance. But with a heavy/formidable 'other weapon' complement anyway, you really should be looking for opportunities to Lock On. Balancing the cost for this uncertainty/indecision is something I find is most easily solved by simply diversifying the role of the escorts: Warden for proper weapons, Castellan for Missiles. This allows the costs to come down and the force to be streamlined for efficiency by the players and designers. Given the Tau's willingness to use allied ships, I see no trouble with this except for those who are very keen to use 'Tau only' fleets, but I find that a difficult audience to cater for, mainly because it doesn't add anything.
Anyway, that's just a quick rehash of the long-standing troubles I've personally had with the fleet reformed to consider this list particularly.
I'll add more in detail when I can! It's really nice to see peeps working on it!