Admiral, PLEASE playtest this. Put bluntly, your idea will create a SM fleet that will get smashed by Chaos or Tau. Don’t think to yourself “fair and balanced†Chaos or Tau. Think “beardy munchkin 16-year old with deep pockets and no personality using all carriers and lances because it’s legal†Chaos or Tau. Your fix for this is to create a SC carrier. How about we do neither, thus we don’t break the SC and then fix it with yet another SC. 
To put it bluntly as you say, SM ARE already getting smashed by Chaos and Tau with the existing SC set-up. This game is not about ordnance. This game is about direct fire weapons and 1 shield ain't enough against those two fleets you mention. I don't need ordnance with Chaos. Why? Chaos already has the lances to smash through SM's pitiful 1 shield stat.
I run this typical 1,500 point Chaos list:
1 Hades
3 Murders
1 Styx
2 Devs.
Yes, Lots of ordnance which mostly I point out are just doing anti-ordnance role. It's the lances which KILL however. 10 lances at 60 cm on Lock On with my Hades and Murders. Tell me the SC isn't going to brace against that much firepower? The lances of the Styx and Devs just doing support role and killing off the cripples. That's in existence NOW, Nate. I punish my opponent's SCs severely everytime with this list.
Now, while I have limited experience with Tau, the fact isTau already has enough ordnace to ignore shields that upping the SC's shields to 2 won't matter. While the SM will lose out a bit on the TH, the fact is they're still resilient fighters and the armor of the SM ships will help a lot in blunting the Tau ordnance attacks. The increase in Shields will matter against the tau's Direct Fire weapons however which are themselves dangerous.
Are you really playing the same SM fleet that everyone is playing? What's a vanilla TH going to do? Why crit an opponent. How is that helpful? Most of my TH go to anti-ordnance roles which they do quite well, thank you but THs themselves do not directly help an SM fleet survive direct fire.
Secondly, what's wrong with the carrier fix? It's fluffy. It's easy to model right out of the box. Either:
a. You use the TONS of IN Launch Bays lying around BFG players bits box or
b. You just drill out the WB bays.
Either are not hard conversions to do.
The “too many hardpoints†issue is not enough in and of itself to revise a baseline profile that has existed for nine years.
Again, what's so hard about invoking a change in policy especially when one does not have to come out with a new model? Will GW or SG suffer a hit on their profits if you change the baseline stat? Will the players suddenly throw out their SCs because they are suddenly worthless (how adding one shield in exchange for a TH point makes the SC poorer is beyond me)?
The baseline profile has existed for 9 years and guess what? People are finding it lackluster.
Warp Rift came out with a Nemesis fleet list that was pretty cool. A LOT of the ships on that list are cool but require some detailed scratchbuilding, but if I recall correctly, the Titan was merely an amped Gothic battlecruiser. I’m not saying “let’s make it official!†I’m merely saying that were we to do so, the model itself wouldn’t be an issue because any novice modeler could make one right out the box.
- Nate
Oh, that Titan. Just to give credit where credit is due, that design originally came from the defunct Blackstone Outpost site. Logical design but extremely overpowered. Much as an IN player, i would like to have it in my fleets, I'm afraid I'll have to say no to allowing it.