Noah, I think the GPS makes you less of a dogman. Your using technology to know what your dogs are doing. A dogman knows already. I think they will teach you a lot about your dogs though.
I completely agree, what I see as a huge advantage(at least in our terrain) is the ability to know sooner when your dogs stop moving and how to get to them most efficiently. What would've taken me 10 min to figure out before, now takes less than 30 seconds, allowing me to get there and help before the hog breaks or dogs get hurt. That's why I let my buddy work the Garmin and I pay attention to the dogs... all I ask him is "are they still moving, and if so, what direction". I can certainly see the gap in dogmanship that the Garmin is creating in many hunters though.