I think the thing you would have to discuss is your intended use. Are you going full time, part time or weekender/holidays? The reason we went from a MDT to a HDT years ago was to be able to handle the weight of the larger trailers and have the the extra power and braking safety that they provide. That also comes with the ability to haul jeeps/cars/SxS's/motorcycles etc and not worry about weight restrictions. Many in the group here optimize the advantage of owning a HDT. It seems to me almost anywhere you can fit a 36ft RV and HDT you usually will fit a 45ft RV and HDT.
The one other thing that isn't mentioned as much is the comfort in driving and riding in a vehicle that isn't bucking you around. My wife has neck and back problems and could only travel maybe 4hrs a day with the one ton dually but in the HDT with some very good seats a 8hr day is no problem. If, you are worried about length don't need the hauling capacity or braking ability then go with a LDT and shorter trailer. Back to the intended use and maybe future plans as a HDT is a great way to future proof maybe going to a larger RV.
Rick & Carey