I`m not sure his behaviour is due to him being entire, so no I would not neuter him yet, once done there is no going back and as its been pointed out, neutering may make him worse.

Why not try an implant first, at least this way you will see if he is better, worse or the same, it will give you time for to mature, before any decisions need to be made.

Obviously your choice For what it is worth, I have two entire male dogs and when I asked my vet about having them castrated he asked 'why?'. I explained that they had at the age of 15 months become quite bolshy, were marking when visiting friends houses with resident bitches and humping a lot. My vet owns male dogs and none of his have been castrated. He suggested the Superlorin implant (male contraceptive). I had the implant done and although it took approx 6 weeks for it to make a difference it did. It hugely lowers the testosterone production, stopped the humping and the marking. (and made their balls shrink ) The implant is injected between the shoulder blades exactly like a micro-ship.

Now I have a choice whether or not they have a further implant when this one wears out. My vet told me in his experience with all of his dogs, one was enough. I'll have to decide in the next 3-4 months. He actually discourages owners of male dogs to have them castrated.

Info on neutering:
http://www.naiaonline.org/pdfs/LongT...uterInDogs.pdf

I stand against the stream on this one.
I would get him neutered personally speaking but I don't think it would change him dramatically.
You can't expect him to behave as you would like if he smells a bitch in season and I just think it makes life easier for both dog and owner if you are never going to breed him.

Why do you do that?

What do you mean by that?

My GSD bitch always did this and we had her from a puppy

You could recondition this movement to mean something good. But you can't do it in one go. You start off slow and reward when you get the behaviour you want, which is the dog to stay calm and relaxed and then build up the speed of movement. I'd Take it very slow and build it up over a number of months.

I think he may be a bit nervous of fast or sudden movements (quite common) but I don't think you have described any dominance