I think 500 credits for "stuff you personally own" is fitting for most AoR campaigns. I agree that it's not a lot of money... but that's kinda the point that FFG seems to be trying to make, both here and in Edge of the Empire.
In EotE, the PCs are 'fringe-types' that are scraping by for the most part, though they're usually lucky enough to have a decent ship that they can call their own. Some might have a few more goods, but there are strings attached.
in AoR, the PCs are "green recruits," most of them having recently joined the Rebellion what what little they could carry on their person. Anything else would be assigned on a "per mission" basis by their superiors, and may not always be available... unless the PCs have managed to set up their own base of operations, in which case they've got considerably more resources at their immediate disposal.
On that note, some rules/guidelines to cover requisitioning gear from the Alliance for those "per mission" cases isn't a bad idea. Galaxy at War for Saga Edition had a pretty decent system that used group level and military rank, so I could see a similar concept being put into place for AoR. Perhaps just a straight credit amount times the party's contribution rank, with a Negotiation roll to try and convince the local quartermaster to supply a bit more, with each success providing an extra percentage's worth of gear... but done with the caveat/understanding that anything not lost or destroyed is returned at the end of the mission.
During the EotE Beta, I voiced the opinion that only 500 for starting credits almost forced a number of PCs to take extra Obligation, particularly those PCs whose character concept revolved around higher-end gear, such as a slicer or a well-armed bounty hunter or a gambler/scoundrel with a small stash of "liquid funds" and a reliable blaster for when things failed to go smooth. But as noted before, the design team's vision for starting PCs seems to be "strapped for cash" and not be walking arsenals.
In a few one-shot games, I've allowed the PCs to start with 1000 credits for starting gear, with the idea being that I'd be lessening the feeling that the players had to take extra Obligation just to be able to start with what they felt was "concept appropriate" equipment, or that they had to choose between said gear and the chance to get a few extra XP. I got yelled at by a few posters about "not following the spirit of the game" by not wanting the PCs to quite so strapped for funds, even though I suggested adding a sidebar to advise/encourage GMs to double or even triple the amount of staring credits a PC got if they felt the campaign warranted such a thing. Maybe that sidebar idea could work for Age of Rebellion, where aside from one background option that the entire party has to agree to, there isn't a way to start with extra money.