No it wasn't. She did nothing when the city fell to Ghaul. Nothing before then. She made deals with potential enemies of humanity and hoards her tech out of pride and selfishness. Saladin, Crow, and Caiatl, dwarf her character development.

She did nothing for the guardians, because she didn't trust light bearers, you know....since her whole family was killed by them. But she expresses multiple times that she wanted to provide means for the non-lightbearers to defend themselves. She was protecting humanity in the way she thought was best, by giving every non guardian her weapons. I don't blame her for distrusting guardians. She's not the only person in the game who does. How many NPC's running around the tower spout stuff off about guardians, and they are working directly with us. Think of how much more the people in the city below distrust us. Guardians have failed a lot. And there have been some bad ones. Lore talks about how early light bearers became despots and warlords, so not all were good. That's why the game has at least 1 guardian whose sole purpose is hunting down evil lightbearers like the Shadows of Yor. But that's getting away from the point. Ada has been around since the beginning of the city, and has been helping mortal humans. She herself, isn't a guardian, and can be killed so why would you expect her to be going out on raids. She's not the only leader in the tower who doesn't go out, either. Zavala himself doesn't do crap except throw up an occasional bubble, and go around yelling at everyone.