Most regular farriers who just do a trim do what's called a flat (or pasture) trim. Basically they're trimming the hoof the same way as they would if they were going to go ahead and put a shoe back on. This means that there is little hoof wall in contact with the ground, so all the weight is on the sole of the foot with no support at all from the hoof wall.
It is important to find a farrier who is trained in actual barefoot trimming, as this is more involved than the regular flat trim that you are currently getting. You will definitely be able to see a difference. :)