Neutering doesn't solve behavior problems. When dogs are outside only when owners can be out there with them, far less things happen. The only good guard sog is a well trained one specifically for that purpose. Pet store puppies csn have all kinds of behavioral issues. Most shelter dogs don't have behavioral problems. Don't punish cetain breeds, but punish owners for not properly supervising dogs when dogs of ANY breed get loose and bite or kill someone or another animal.
Pack behaviour is very interesting and the difference in behaviour of dogs who live in a family with another dog. Also dominance and how the alpha male disciplines other dogs. One of my dogs has a habit of "conducting his own walks" ie running off while we are walking into other fields and when he returns after much calling, the alpha male dog "tells him off" and bites his neck (not hard!).
There are a lot of aspects you can look at though.
how about the imprinting period or whatever you would call it, the age where puppies more or less soak up knowledge, and how the effect of how the dog is treated in this period, geting maximum out of it, or in worst cases teaching it many bad behaviors or expose it too bad situations making it very fearfull and nervous
the period is important because how you behave in this curiousity age where they so easily soak up new knowledge can be a massive tool in helping shaping them into good citizens or starting off on the wrong foot
I like the subject of surrogacy and the effects of a false pregnancy in a dog.
We have a spayed 12 yo Yorkshire Terrier/ Chihuahua mix is having a false pregnancy right now assumed by our vet to be triggered by our puppy.
I also like the subject of the bonding between dogs. Why some really bond (to an abnormal level) and why some don't. Why some with one person and not another.
How bout, interaction between two dogs.
How one dog initiates play and the other signals agreement.
How it differs under different circumstances
-when the dogs are familiar with each other vs strangers
-when one dog is bigger/stronger than the other
-when one dog is a puppy and the other a mature adult.
-when there are more than two dogs present.
Whether dogs establish a hierarchy amongst themselves, and how.