Your tongue weight is included in the UVW. So probably 7000 lbs is more the number to focus on. How long is it? That matters too. A newer half ton will pull a 7000 lb TT fine. An HD will just do it better, especially if it's a diesel. Think about how far you'll be towing, in what parts of the country (mountain passes, elevation), whether you plan to upgrade in the future, what would the truck otherwise be used for, etc.
Me personally, if I didn't have a trailer at all I'd still be driving a HD diesel. I just flat like them better, and have since I was a dumb kid growing up on a farm (some things never change I guess). I like the torque, the sound, the heavy components and the way it idles down a highway effortlessly whether its just me or I've got the whole family and our 11k lb fifth wheel in tow. Others really prefer half tons and their softer rides. Neither preference is better than the other, just different.