Can you get us some better pics so we can tell you if you need a new farrier? What does the farrier mean by keep her trimmed "high and tight"? Did the farrier even come out to see the foot?
When there is damage through the coronet band, the hoof can be affected permanently. The coronet band is like a human fingernail bed, where if you damage it then you will have a weird fingernail for life. The hoof may always grow weird but that's not to say it will be a big problem. Since the injury happened 3 years ago I would assume this is going to be a chronic issue. You will need a farrier with some good knowledge to help keep this hoof in the best shape it can be. I had a mare that had a similar injury, the hoof was always a weird shape and she was never lame. She was always kept shod. I have a feeling that this is not being managed properly by either farrier because of what patty said...the heel is too forward and stressing the damaged area. The heels didn't get that way overnight. Please post some more photos for us?