I have just switched from a 2010 Tundra to a 13 Ram 3500 due to moving to a larger 5th. Had I not done that, I would still be in my Tundra pulling my 8500 lb 34' WindJammer.
I think it's appropriate to use the right tool for the job. When hammering nails, you can use a Sledge hammer...but why would you when the right tool is a claw hammer. I don't regret my choice to go diesel, but I did it because the job changed and the tool needed to as well.
The current crop of 1/2 ton trucks will all do an amazing job up to 9K without any issues - as long as they are configured properly. I have a hard time seeing why you wouldn't go gasser configured the way you want. All of the gas engines are pretty rock solid. I don't think you'll be disappointed.