I personally don't think that shoes are going to help her hoof quality. Abscessing frequently tells me there is something else going on.
I think one thing to try is perhaps leaving a tad more hoof wall when trimmed. I'm talking about 1/16th-1/8th of an inch more than what is being left already for a couple of trims. If your horse is frequently on gravel and soft terrain, this is an option. If your horse is more often on concrete, then it's not a good choice.
The slight extra wall would raise her off the ground a little, lessening the impact of the gravel as she runs accross. And provides great traction in mud.
The farrier should be using a good mustang roll or bevel all the way around the foot-this changes the mechanics of the hoof to encourage a more concave sole and he shouldn't remove any sole, even if it's flaking and cracking, when trimming-the dead sole would help to cushion agains the rocks and prevent bruising which leads to abscessing.
Shoes would lift the foot higher, but not solve the problem. It would encoruage the foot to spread flatter, so when then there's never a good concavity and still prone to bruising, esp if you remove the shoes again or one falls off. Also, the sole is usually cut for shoe prep, further weakening the body's protection.
Boots such as Old Macs can be used in turnout for a while. There is more work involved, you would have to remove them every day and let them air out to prevent thrush problems.
If you did turnout with boots, padded inserts would help to build the sole your horse needs to go barefoot on rocks. The sole needs stimualtion and short term protection and boots can protect and get the horse comfortable enough to move more,which means there will be more growth, and sole will build quicker than leaving it naked and the horse doesn't move as much.Either way,the sole will build, but a couple of months in boots can really speed up the process.