I'd have the chiro take a look, then saddle fit, then if all checked ok, I'd put her over some trot poles (Cavaletti) to MAKE her pick those feet up. This was part and parcel of Rascals rehab. It does wonders.
BTW yes, I know she is gaited, but she can still do the trot poles and build the booty. Hill work at a walk is good also. Once you start building the muscle and if she is still doing it, she may not be reaching far enough under herself because she is lazy. What kind of conditioning are you doing, how old is she, is she on a regular workout schedule? Sorry but these things need to be considered also....
Rascal forges and if I forget to put his boots on, he'll short stride with his back end to stop himself clipping his heels. Almost corrected the forging with a good farrier though :)
I might get shot telling you to trot her out instead of worrying about the gait so much, but Meh, trotting works.
I miss you Rascal. Every day, all day.