As for the suggested changes, they'd all sacrifice realism, and gain none of the balance you want.
1. Group heavies together into duals and quads, along with scaling the ship down.
The Executor, Sovereign and Eclipse are all already scaled down to a third of what they "should" be. Scale them down any more, and they'll be too small, and the hardpoints would all start to overlap. If we did that along with grouping the turbos togther into duals and quads, you're just increasing the concentration of the hardpoints, which would make them even more powerful and more than make up for the slight loss in firepower from switching. Right now it can probably bring a sixth of its weapons on to any one target at most, but if you make the ship smaller with fewer hardpoints, that would probably go up to about half. And if we reduce the numbers on the Executor, the same has to be done on the Eclipe, and then on the Sovereign, until the Sovereign is about equal to an ISD with a superlaser, which really throws off the balance. The alternative is have Executors closer to Sovereigns and the Eclipse in firepower, which renders the Executor basically pointless.
Sure, the Executor has 140ish hardpoints, but regular capital ships can have between 12 and 20, some of them a lot more powerful (Executor doesn't have a single dual or quad I don't think, whereas the Republic SD for example has 6 Dual Heavies, which is essentially 18 regular turbos, in addition to 6 more Heavy turbos, which is more like nine. So on that ship alone you have the equivalent of 27 weapons. If you adjust the Executor in the same way you come to about 170 weapons I think, which is only the power of 7 Republic SDs, which have better Fighter compliments.
^^ THIS is it! I used frigates and corvettes but they literally get fried
Frigates just don't have the shield and hull strength to stand up to an Executor, and both corvettes and frigates tend to lack the firepower needed. They typically have lasers instead of turbos, which are terrible against non-fighters.
In the light of knowledge I have recently gained from replies here I think I should rephrase. Executor seems very well balanced now.
My suggestion has now moved to rather elementary level. I think you have done damn good job finding some sort of mark between realism and gameplay for most of the ships. Except Executor. As I wrote in last post I would prefer to sacrifice more of realism to behalf to more "playability" of Executor. Accepting rather a crripled version possessing lesser power and costing fewer credits for possibility to see Executors more often in GC and in skirmishes maybe one day. I understand that this cannot work for all SSDs because Eclipse and Sovereign having Superlaser.
The version we have now is actually somewhat crippled; shield, hull and firing rates are all way less than they should be, and there's even fewer weapons than there should be. About three quarters of what should be there by our representation system is. The entire point is that they're rare, that's why they can be as powerful as they are, but they are by no means invincible or absent; even playing through The Hunt for Zsinj, I typically run into one or two (excluding Iron Fist). But as Enc says, you will never see them in skirmish.
The main changes between v1.0 to v1.1 is the shields have been weakened and the health of each hardpoint has been increased. The problem that people who say it's too powerful typically have is by the time they are able to actually start targeting the weapons, their fleet has been decimated. This way, shields shouldn't last as long, but its made up for by the individual hardpoints lasting a bit longer.
Also:
Before:
http://screenshot.xfire.com/s/108233542-3.jpgAfter:
http://screenshot.xfire.com/s/108234527-3.jpgThe remaining Carrack and Assault Cruiser were both within one or two hardpoints of death, Mon Remonda and Song of War esceped more or less entirely intact, my Star Destroyer and Dominator both lost about half their hardpoints.