
Corellian ships should be more common in general in my opinion.
If you ever read the lore about them, they are one of the most famous ships out there (correllians) for trade, build and think missions

linear ship lvling sounds cool, every lvl you could get a bunch of ships available - if it's possible you could bind this not even to racial rank but even to fight/trade rank as well
As you all know, only the elite were allowed to fly TIE fighter, same as renegate squad e.g. some standard ships could be available early and enhanced editions later, warships even later when you rised your rank high enough.
About the star destroyers:
every ship has its pros and cons, IMO victory fits very well where it is currently.
The amount of ships available in star wars universe should be enough to give even seemless "useless" positions a bunch of ships available - for insance: I havent figured out for example what i could use a nebulonB for - but it's a nice ship either way.