Beregorn: So, basically, they add no new content, use mod available from the first release and don't allow me to install the unfinished business and all the other mods. This is "enhanced" how?
Thankfully I still own a physical copy...
Most of the changes are under the hood. They ported it to their modified BG2 engine, the underlying UI code has all been rewritten, so the UI is now highly moddable. The underlying code for the spell system has been completely rewritten. Plus, there's a bunch of opcodes and new functionality that's exposed to modders instead of being hard coded.
It didn't take long for BG1 and 2 mods to get updated when their EEs came out, so it shouldn't take very long for PST. One of the beta testers created a containers mod a couple of days after testing started, so we should start seeing new mods coming out pretty quick.