Neutering should not affect his protective instincts. You're absolutely right about him being easier to handle, and as far as being around females in heat, well, if he's intact you WON'T be able to handle him. Attempts to override such a strong, uncontrollable (yes, I said uncontrollable) and instinctual action can have very, very bad results, and an intact male dog shouldn't be held accountable for what happens in the throes of that situation, but the owner certainly would be.
Many men have a real problem with having a male dog neutered. It's a guy thing. But you're absolutely right, especially if you want him to participate in any kind of group activities.
That doesn't even begin to address the health and safety issues.
As far as when to do it, well, most of my dogs have been rescued as adults and were neutered after they were grown. I can see the point of waiting until the dog is through adolescence; possibly two years old as testosterone levels do have an impact on muscular development; on the other hand, you'll need to stay on top of everything to make certain you curtail any possible dominance issues within your pack family. It's imperative that those kinds of attitudes aren't allowed to become problems, especially in a guardian breed.