Classes (from smallest to largest)
Light Bomber Craft
Medium Bomber Craft
Heavy Bomber Craft
That's a lot of different types. I thought the point of having ship design is to have some real freedom in building your fleet. If one type of ship counters another, what do the Hp/damage/etc stats matter? You may as well just have regular Civilization-style units, where you research tech and you get a unit that has stats X, Y and Z.
The sins system of combat works perfectly (or so close to it I cannot tell the difference). The GC2 system of combat does not. It would make sense that to create a fully balenced, decisive combat system for GC2, I would have to borrow a little from sins to make the thing work.
That's patently ludicous. There are any number of TBS games with functional combat systems; if you feel that GC2's combat system doesn't work, they could look into any of those.
Stardock did do something with combat that hardly any other game offers, the ability to have 3 different types of attacks and 3 different types of defenses. I'm sure there are a few other games that do this, but it was a new approach, and would work astonishly well if the AI knew how to actually 'cope' by changing their ships up better
I'm not so sure it would have worked "astonishly well" with better AI. Towards the late-game, changing your entire army's attack/defenses requires a massive quantity of money. During that time, your attack is stalled or your defenses are ineffective. Sure, if you could do it, it would work, but if you could do it, you probably had the economic advantage anyway and are going to win a priori.
It just makes an already existing economic advantage even more advantageous.
Look at Elemental. Supposedly it will use the same basic mechanics and engine as GC3.
No; they never said that. It would be using the same engine, but that doesn't mean anything about its gameplay.
You can mod CivIV into something not entirely unlike GC2. That doesn't mean that CivIV plays a lot like GC2.
Although unit creation is quite fascinating being able to create knights based on needing to have a source of horses, trained men, leather for saddles, iron for swords shields and armor... Stardock is really on to something with some great ideas there.
That idea seems in need of some form of regression. It's the beginnings of a good idea, but I don't think it will work in this form. TBS games work best when they abstract concepts down to simple forms that create complexity through their interactions. There's some significant simplification that this idea could use, to distill it down to its essential features.