It's quite possible that the farrier removed too much sole, complicating the already soft foot situation. I disagree about the shoes, as is probably no suprise. =) But I think if she's has such thin sole, and esp with a softer hoof capsule, the coffin joint may very well "sink" further into the hoof capsule, flattening the sole more, and making her very likely to bruise.
Right now, esp without pics, I'd probably stay off the hard ground, she could very well be telling you her foot simply isn't capable of it, and could bruise very badly and turn into a sever subsolar abscess. Sometimes it si simply a matter of needing to toughen up with more stimulation, but sometimes that can cause major setbacks. If she was trimmed too short, a couple more weeks may be all she needs to be comfortable again. However, in neglect cases, that is rarely the case, they usually have some other pathologies going on that take time to really get their feet right, along with some good professional hoof care.
You can always see about some hoof boots to exercise her in so you don't have to worry about the ground surface, as usually exercise is the best way to grow healthy hoof back in. Hoof boots offer not only protection from rocks, but allow the hoof to flex and perform more normally with less concussion than metal shoes can offer. Metal shoes only really protect the hoof wall, which is may not be what hurts her (it's probably too much pressure on a thin sole). Metal shoes just don't support normal hoof function, they can really just mask other problems.