There have been a lot of good responses to your question. I agree with most of them. Camping in a Casita will be different than camping in a larger box trailer. Only you can decide to what extent that will impact your decision.
But, to answer your question, the Casita will be an easier tow, perhaps not a lot easier but easier than the larger box. A wider an longer trailer is a bit harder to deal with. Backing, parking and pulling into gas stations and tight spots is easier with a more narrow trailer.
I pulled a white box and now tow an Airstream. The Airstream is wider and it is harder to see around and I have to be more careful when towing it into tight spots. It is also 5 feet longer and 2000 pounds heavier than my old white box. Towing both of them with the same truck I get the same gas mileage and that is all because of the shape of the trailer. Those who have mentioned this about the Casita are spot on. I also don't worry about how stiff winds and passing trucks affect the Airstream. For ease of towing I can't see how you could beat the Casita.
