Fluff is great, but since this is a GAME, playtest balance will ALWAYS supersede fluff, period. Fluff will always be modified to support game balance, not vice versa, and that guidance came to the HA's straight from the designers.
Whew! I'm glad to finally hear someone say that and it's all the sweeter coming from HA!

Concerning the 2 shield 1 T-hawk SC and 3 T-hawk SC:
I agree with doing this, but I don't think you've heard me arguing anything "fluffy", as I'm not qualified to do so. My argument is grounded in the intention of making the SM fleet a little more dynamic with fleet building and to make them more enjoyable to play against in any scenario. Please forgive me if I'm being a broken record...
I don't view the 3 T-hawk SC as a "fix" for something I've just broken with a 1 T-hawk base. I view it as a re-distribution of T-hawks so they are not so evenly spread. I believe that this actually promotes MORE thought on the side of both players in the game. For the Commander to choose where he needs the most T-hawks on the table, how he will protect his T-hawk nest egg, and it creates a more enjoyable experience for the opponent because he must work to attack the SCs most relevant to his threat (i.e. the t-hawk carrier, the up-gunned SC, or the vanilla).
I don't even think it's a "no brainer" to take a 3 t-hawk SC to fill the gap. I believe, like the BC prow option, that it's an opportunity cost of points and not taking either of the other 2 better gunned vessels. The whole point in my mind is to give a SM commander an option to tactically depend on T-hawks in his fleet or bombardment cannons, or some combination of the two ( whatever fits his/her style of play). Currently SCs are a "no brainer". You get one choice that is a jack of all trades, but a master of none. The BC option is a great addition to what I'm talking about accomplishing!
Now, the entire conversation about the BC prow upgrade is to ensure the best possible trade for t-hawks, meaning that a commander should be able to have a competitive fleet with fewer Thunderhawks on the table if he so chooses to depend on getting stuck in with BCs and torps (after all BCs remove ordnance waves on +4 right? ). So, I don't see the necessity of always picking a carrier just to get those t-hawks back, because that could deny me more BCs on the table!
A think this is a different angle then others are taking on it, but I hope you'll see the validity of the design suggestion. Side note: I understand your desire to not touch the base SC, but maybe give it another consideration

Ah, and I have not play tested this yet in fairness. I still have to run through the BC stuff on Monday and Tuesday!
Russ