Well, conversion from push/pull to turn probably isn't possible without changing the valve. Plus, a valve that old doesn't have the required new safety anti-scald features. So, While you are remodeling, I'd change the valve, get something you like the look of, and get the new safety features. Personally, I like the thermostatic valves, but those cost more than the other approved type (pressure balanced). Keep in mind that with the new valves, typically, only the thermostatic valves have a volume control if that is important to you.