I'm not surprised you found the 5.9L Magnum wanting after getting out of a 5.7L Hemi! The difference between the two engines is night and day, and the chassis you're used to is much more refined than the older truck's, although the older truck might be rated a little higher in towing capacity. If you have 17" wheels and 3.92s in your 2010 along with the factory tow package, you're probably good to go for 10,000lbs of towing.
If I were you, I'd start saving money for your next newer truck instead of trading now. The 2011 I paid $25K for in 2013 with 30K miles would now cost me $35-$40K to replace with a used newer truck. Get as much mileage out of the 2010 as you can before something expensive happens to it, then retire it and replace it. Stuff like replacing the seat covers, doing a good interior cleaning, touching up the paint, etc., can go a long way towards refreshing your current truck and making it more enjoyable to drive. My '11 has 97K on it, still drives like the day I got it, no visible rust, and is paid for. If I get another 100K out of it like you've gotten with yours, it will be overall the least expensive vehicle I've ever owned.