I wouldn't be concerned. My horse wraps herself around my farrier, she loves her so much. She's gotten her nose bonked with the rasp a few times. My horse has always been a cuddler. My friend's stud leans on his farrier too. I don't think it's a balance issue, or a health issue. It's just how she is.
And think about it, if someone is holding one of your legs up for forever, wouldn't you want to lean on them too?