What you are seeing is very normal behavior for an unaltered male cat. He will probably start spraying in the near future as well as the constant vocalization. The only way to help stop this behavior and possibly encourage a little more affection on his part is neutering him. It will take a few weeks after neutering for his hormone levels to drop. Intact male cats can also be somewhat unpredictable in their attitude. I had one of my stud males attack my leg one day for no reason and he had always been a very calm, quiet boy that was easy to handle. He's never done anything like it since, but it's not unusual for them to do things like that when their hormone levels are high - especially if they haven't been breeding much.
Sometimes, putting them on Buspar for a few weeks after neutering will help with the attitude, but it is a fruitless and unfair thing to give them if the neutering doesn't go along with the drug.
Please let me know if I can help further.
Breeder
16 yrs health care mgmt & issues focusing on cats, reproductive issues & multicat environments