Definitely agree on that. I’m going to be creating a plugin with more advanced VFX features, like modules for Cascade and suchlike. There should be some kind of option that allows people to trial things before they buy them too, though in the case of blueprints that wouldn’t really work.
I don’t think anybody is going to make anything out of selling blueprints on the marketplace. At least if they do, it’s not going to be a long-term source of income. C++ and 3D Models will probably take up the majority of the marketplace content.
I also agree that Epic should take their cut straight through the marketplace, to prevent any faffing about. Allowing the content creators to create some kind of licensing system for their content would be nice too, piracy is a pretty lame problem, and it’s your own fault as a developer if you make things too expensive, but I don’t want my plug-ins and stuff being distributed between an entire team if only one user has purchased it. The engine flagging them up and disabling the features if it doesn’t detect the right licensing properties would be good. Trouble is with engine source they could remove that functionality anyway unless you write a clever plugin 
No licensing system is perfect or fool-proof of course, but it would filter out most of the problem. Only really possible for compiled C++ sales though.