As a person who put a good amount of time playing Ambra in both the beta and the full game I will say this. On a base level when starting a match with only helix level one mods up and no gear just about any other support can out preform her in every aspect from self sustainability to damage output.
Her life steal is weaker then Rathās and with the nurfs made to her Staff or Radianceās range she has to play in Melee range to use here staff at all effectively. This would be less of an issue if it had a better time tracking opponentās when she aimed at them directly vs her just holding staff out and running at face 
Her Sunspots function as a decent option to help do damage and heal Ambra and others but they are to fragile to be effective as a group healing tool and doing damage at the same time without helix mods. It makes here early game really tough as placing Sunspots correctly can be the difference in thousends of damage and healling. Once you have verying helix mods Sunspots function as a potent avinue of doing both damage and healling at the same time while giving your more leniency. On the topic of early game I think they work ok for the level of difficulty she is listed as, that difficulty being (Complex)
Solar wind functions just fine imo its damage is modest for the amount of Heat it generates allowing more damage output and it functions as a potent utility with later helix mods. On the topic of early game it works just fine.
Here level of servivability is modist if not a little low as if she finds herself in danager at the start of a match here Fire Shield seems to disappear in a single hit no matter what and here hp has to fall yo 20% for that to happen in short it helps in a jam for her but dose nothing to aid her team or healing and is imo one of the weakest points of here character as it tries to encorage you to play in melee but dose not reward you with the same results othere can acomplish in the same position.
All and all I personally think here Staff is what needs some attention right now it if it is going to have melee range beam it needs the kind of damage a melee character can pull out, given the fact that it can not crit it needs a higher base to stay compeditve, her life steal should remain where it is or be brough down. With here Staffs damage going up she will get more hp from the same % of life steal.
I love how she playes its just a matter of she under preformes until you get helix mods up and there is little you can do about it. God help you if you pick a bad helix by mistake 
Hope she gets some attention soon or elese she may start to lose more representation in game.