In fact, with P5's ability to group, organize, and collapse morphs, it's arguable that these morph-heavy figures are actually easier to use on that platform. DAZ's current policy concerning P5 likely stems from a number of reasons, the primary one being that the majority of their customer base still uses P4. Lowest common denominator, y'know. Some of the clothing takes advantage of P4's crosstalk bug (the superconforming "feature"), so that won't work automatically in P5, but you can copy/paste the character's morph dial settings to the clothing manually in a matter of seconds. Material settings might require some tweaking, especially in regard to bump maps and the Ambient channel. Some people initially had problems with Victoria 3's injection pose system, but I believe that issue has since been resolved; just make certain that the morph files are installed in the default P5 runtime, as P5 looks there for them first.