if you don't think a blue healer is quite the fit, a corgi is pretty good for the herding and can also be good at protecting and tracking. actually used for herding cattle and known for the 'corgi roll' when a cow would try to kick at them when they would nip at the cow's leg to move them.
Ein came to us when he was 7 months old and not house trained or knowing any commands. within the first few days of owning him i was able to train him to sit with both a voiced command and shortly after that he seemed to understand the hand command (basically 'stop'). he also learned quickly how to give me his paws, touch nose to my hand, 'out' when he needs to be out of a room, 'come', 'lay down' and 'sit up'. the only thing i can't get him to fully understand is 'stay', but the 'sit' hand command seems to work. i also have him used to a few whistle commands for 'come'. o, and he knows that 'home' means the basement door, and 'kitchen' means the kitchen door which means he has to go up the backyard stairs to get to it.
i'm still working with him to not chase my girls when they run but some of the girls have learned that he won't bite them if they just mozy about their business, just trying to lick their feathers and check them over once in awhile. the roosters just give him a peck on the nose when he gets a little pushy with them. he's a good boy at letting us know when someone is coming to the door or into the yard. he will give a couple of sharp barks or stare at attention till he knows if it is friend of foe. he will give his broadside between one of us and someone/thing he is unsure of. (butts the cat from getting to me most of the time like this!)
i have yet to take him to a trainer or an obedience class but have not had any issues that i've come across yet.
corgis need training for the herding/guarding/tracking and love to please (like most breeds), but can get quickly bored if not kept busy with a job. they can also be a little nippy as pups/young adults so caution when training gets them excited. mine has figured this out and when he nips accidentally while playing and realizes it, you just feel his teeth on your skin and no pressure behind it.
some corgis can be barkers, mine has been relatively quiet and only barks when he gets excited while playing and wants the toy or hears a noise outside that is disturbing. i've only had to deal with spring shedding once so far but they are very clean dogs-mud slides off their fur and they quickly dry off.