I am all for neutering. I waited until Gargamel was 2, and wish I had done it sooo much sooner. No more humping, no more marking and no more looking for Dogs to watch or play or fight with on walks. He sees them and listens as we walk by, where before he could not leave until he physically saw them. This is just in the 3 1/2 weeks he has been neutered. He used to take forever to get his attention away from other dogs, now he looks, but will walk away with me without a problem. He is a great dog and listens OK, but after the neuter I only tell him one time to come and he is coming! or I yell for him in the back yard with his unbreakoball and I could not get his attention, now he looks up as soon as I call him (and goes back to the ball lol but pre-neuter that didnt happen, he heard NOTHING else) that what scared me because of his determination. I know its early, and I know he will only get better. He seems less anxious and less one track mind. If I had known I would have done it from the beginning. Has not changed his personality for the worse at all. Just good things, and I was so worried since he is so great. Also, not to be gross, but his discharge type stuff he had ALL THE TIME on his penis is now gone. I have him on my furniture now becasue he isn;t leaving nasty stain white spots behind anymore!!
In regards to your pup, I just think thats how they play, Mel nips at every others dogs paws when he plays. He "girlfirned" is also a Pit and thats how they ahve ALWAYS played, chase, nip front paws, chanse again. If your dog is dog aggressive, neutering him will not change that, but it will certainly help and not get you thinking "what if"...
Also, other neutered dogs could ahve issue with intact males. I say neuter so that your giving him the best possible life. Your small dog might not like him cause he IS intact and it might cause problems on that scenerio too.