i think this fits under my last post, but there are ways to make your dog enjoy it. If you ignore your dog for an hour as you train, no breed will be happy with that. But if you break every 5-10 minutes (which is helpful anyway) and spend the break playong with your dog, most dogs will be more than happy to wait for playtime. Once they learn the routine.I'd say depends on the dog and what you're thinking as far as him training with you. I've had German shepherds most of my life. I train solo with my dog around. You can use it to help obedience training. Specifically working the dogs impulse control. The dog I have now hit a double end bag and ripped it down when he was younger. I hit the bag a couple of times then the furry missile flew in. I can say that impulse control is a big part of training certain dogs, and is an immense help in overall obedience. The same dog can now hold a down while I'm doing bag work. Which translates to him being able to control his impulses to chase/bite etc other things. I don't do any type of partner work with him around. For one, muzzled he'd still be a danger to my partner, and two, I don't want to desensitize him to someone "acting aggressively" towards me.
Just my two cents