So I think Guardian is in an actually pretty good place right now after playing a couple of matches with her. (I didn't buy her right away) But I think she's in need of a small boost to her kit to be a better pick in matches because she doesn't currently reach her potential with the kit she has. So her biggest problems in my opinion are her lack of distance protection (her sky shield is very close quarters) and her lack of any regen on health. Here's my proposed fixes:
Allow skyshield to be mobile.
Much like Kira's laser, Guardian should be able to throw down sky shield and then tell it to move to a certain location (just like the teaser that was released on Twitter). This allows her to remain hidden, and still protect her teammates from behind cover. It wouldn't break the game at all, but it would allow for further options in the ability.
Decrease the time till personal health regen and make it faster.
Allow Guardian to start regenerating health faster than other mercs, and let her get it back slightly faster. She doesn't have good sustain for the fact that she needs to be close to the front line to be useful. (especially on EV maps) To have faster health regen would allow her to be more viable as the front line protector she is made it be.
Too glam to give a damn.
In game as Seebetterfromadistance.