This is totally out of the realm of Star Wars and would be a total conversion mod. Basically, since I'm no good at modding games I thought I'd throw this out into the modding forum to see if anyone was willing to take up the challenge once EaW has come out.
The two factions would of course be the Humans and the Combine.
The mod would be a big challenge for anyone but would make a great game.
I just wondered if anyone else thought this would be a good idea?

Is the headcrab species guys going to be pirate or something, because that is an interesting Idea. It would be interesting and I would think I might be a programmer if this ever becomes a total conversion, but first I would need to get some programming experience.

Intriguing...very.

Ships for combine could include the vast bizarre array including the walkers, etc. Ships for the humans could include "dog". Would certainly be a unique take on what is, by far, the best FPS ever created (truly a masterpiece, even though I usually abhor FPSs--if you haven't played HL2, believe me when I say it's spectacular!).

The mod has merit, though it would take a lot of fleshing out for balance. Basically on the human side there would largely be heroes (Alex, Gordon Freeman) while the combine is a MASSIVE presence with little intelligence. From a RTS point it would be a big challenge.

Just my $.02.

Dog would be a hero. So would Freeman. Different alien species will enhabit the planets in the same way they do in EaW, but would tend to be more hostile than friendly I think.

As for the actual idea to the mod, I thought the Human faction should be very like the Rebellion in that they don't have the fire power of the Combine, or the numbers, but have cheaper units and tend to be more sneaky in their tactics.

I think anyone that's played HL2 will agree with me that transforming it into a RTS is kind of like producing episodes 7, 8 and 9 of the Star Wars series on your own, it's quite a feat since the programming will be rather extreme and trying to make one of the greatest FPS into an RTS adds a lot of pressure to the mix.

There are many gaps in the mod which would need a bit of imagination for creating things like the buildings or space units but the land battles would be great! Imagine a couple of Striders taking on a few jeeps and groups of humans, it would be great to play! Great to watch too!

Perhaps for a halflife 2 mod, maybe it'd be better if you replaced the galatic map of planets with something of a top down view of a city. And each planet would be a district of the city (in this case city 17 :p).