The definitions appear to have evolved over time, and I believe they will continue to do so. At present each manufacturer seems to be building and defining Park, destination trailers as they wish.
I believe that the newer diesel trucks with their massive tow rating increases made for a TT market that did not previously exist.
I have been seriously considering such a trailer for a few years as my next TT.
I presently have two bathrooms in my Sabre, and do not want to give that up. Such models are pretty rare in a standard TT, but pretty common in the larger Park, etc. trailers.
I had previously noted the small CC many had, but that appears to be increasing with the latest builds.
At this time, I am leaning towards a large 5th Toyhauler, but the so called Park/Destination trailers do appeal to me.