Would I ever be happy towing with a half ton truck

You can get away with a properly equipped 1/2 ton. I towed with my old Tundra for 10 years before getting a bigger truck. Even towed about 8,000 lbs with it for over 3 years.

But based on your comment of possibly moving up in size of trailer, I would say it's a no brainer; go with the 3/4 ton, the cost difference is not that much and will give you more options on what you can tow.