I know of games with detailed space combat and frequent space combat, but not both so this would be interesting.

Perhaps you could make it sort of Star Wars but sort of not, if that makes any sense. The idea of a galactic scale rebellion is a good one in my opinion, but I just never got into the whole Jedi and Death Star thing myself which sort of puts you off the films overall. I wasn't sure if this is what you meant by Star Wars in a parallel universe.

Hangars etc would be very good. I know Miriani has some rooms within ships, and the unreleased Slipgate Legacy (still in development) has some more, but the more the merrier and this could be interesting. Especially so if larger ships with shuttles or fighters could be a normal thing, rather than being rare or almost nonexistent. The carriers in Miriani are almost never used, except when someone wants to use them to run a party (?!?). (edit: party event like a birthday party etc, not a group party)

It might also, or might not, be worth toning down some fighters FTL ability too. You could perhaps have some fighters which have long range, but others which are more likely to use FTL for shorter trips or scouting ahead of their base ship.

I'm also curious as to what your positions would be on PK and player death? I've tried a Trek mush that has permadeath, and it seems to kill combat since nobody wants their character to be at risk... either that or nobody wants to upset the politics. Maybe NPC ships would help if politics was a big thing, so players have someone else to fight. Just thinking "out loud" so to speak here, so sorry if it seems messy.

edit 2:
By sort of SW sort of not I mean make it close enough that SW players can get into it, but just that little bit different that people who aren't into SW's setting entirely can enjoy it too.

Being able to design ship interiors sounds fantastic to me, as does having control over mob ships. I hope you can keep us posted because whilst I am not exactly a Star Wars fan overall I think it sounds good.

I always found the films rather weird and offputting, but I did oddly enough find the computer games enjoyable while I had sight - X-Wing, Tie Fighter, DF 2 Jedi Knight that type of thing. The gameplay was always huge, and so long as they didn't focus on guys breathing through toilet rolls I could more than live with the plots.

I am very glad to hear you have a friend who is also interested in the mud.
That is an interesting issue, player control of governments.
I see a couple options.
1. Let game staff run the two superpower governments for the sake of improving rp.
They would have members who are not staff members, but maybe it could be for players looking for social rp and or politics.
Player run governments could overtake the superpowers if they use the wright strategies, but the superpower clans would do there best to prevent that in roleplay terms.

2. Have one superpower clan run by the staff with only staff members allowed to be members.
Player run governments could only take three planets each.
The superpower could constantly work to bring the entire galaxy under its control by proxy through taxes, terrorism, or blockades, or by bombing the people of a world into extenction.
By proxy I mean, mercinary or smuggling or diplomatic type organizations would attack an enemy on behaf of the superpower.

As for your earlier post about player death, how does the option of registering for pk sound?
It would apply for ground based combat.
I can not think of a realistic way to prevent it in space, its important on the ground because some people are not able to fight effectively especially with some people using triggers and multi command aliases.
It takes 20 seconds to two minutes to die on the ground in player verses player combat, but large ships can be in battle for anwhere from 5030 minutes depending on battle readiness.
One thing I imagine you will like is, your ships computer can be configured to scramble interceptors whenever an enemy is spotted, to blockade a planet, and to fire back at enemies.
Of course the computer is not nearly as good at combat as even a beginner pilot, but a squadron of interceptors plus the powerful turbolasers of the mothership are enough to seriusly damage a ship in less than a minute, even to destroy it if the target ship sticks around too long.