I love my 12 2500 CTD. I've thought the same thing once in awhile. Then I read the mpg reports for the 3/4 ton gassers. I get better mpgs except for in town, which is a wash. However if I only towed what the OP does I might be inclined to trade. We do 4-5000 miles a year, which about 50% of my driving, so I feel it' warranted.
To the OP if you bought like I did and got $10,000 off msrp you could very well be in a good position to try and sell it out right. Trading it will hurt. But a private party sale could be the thing to do.