I reckon go for it as long as you keep an eye on your mares hooves
I event barefoot on my tb mare but she hasn't been shod since she was trialed at the race track so its a bit different, She isn't "barefoot trimmed" or anything shes just unshod, I also do endurance with her and we cover all terrain types and shes never once come up lame at the vet checks.
With the whole slipping issue, As long as you balance the horse and set her up right before the jump and not on insane angles then there is no reason for her to slip, Some people with studs ride all out because they have this false security that they wont slip and more often than not they are the ones who get in sticky situations
But then again i'm in New Zealand and our xc courses are very different
Keep us posted :)