One thing I will say about Gara is she's an incredibly functional frame with even a very limited mod loadout, so if new players CAN get her, she's well worth their time. For reference, I think someone's pretty well off with a few points in Redirection, Vitality, and/or Steel Fiber, and has a maxed Intensify, Flow, and Stretch. 90% damage reduction, a great defensive ability in 4, a good melee ability with 1, and a mostly ignorable 3rd ability. She is very oriented towards defense for the most part, though--her 4th ability is the most defining with regards to her playstyle.

I do think she's a bit hard to get for newer players, but it isn't entirely unobtainable. A new player with a close-to-maxed Serration, Split Chamber, both 90% elementals so as to yield Corrosive, and basic crit mods, should have enough damage to handle the highest tier of bounty. This isn't really something new players would have, but pairing an okay weapon with those mods with a slightly modded rank 30 frame should be able to get the job done, with teammates.

That sort of goal is potentially reached within a week or two of playing, how I see it. You can get a pretty decent mod setup by Europa. Not that most players will or need to, but it's possible I think. I think I would recommend that most new players avoid Mag right off the bat, then shoot for Rhino. They should then try and pick up Frost or Trinity. From there, Gara, Valkyr, Nova, or Equinox would be a good choice.