So, your SSD might have the side effect of improving script performance but the formula isn't faster hard drive = better scripts or suddenly different script VM constraints. Papyrus performance is directly tied to framerate. SSDs will help with asset load times and possibly your framerate.

There will always be a performance constraint and if they raise the constraint people will just install more mods until they meet that constraint again and then repeat. The complete list of Skyrim Special Edition console commands is insanely long, and savvy PC players can change just-about anything in the world with a few commands. Truly, there's not much wrong with the Papyrus subsystem itself, the problem is modders writing underperforming code / not handling errors and exceptions, and users installing way too many scripted mods. Performance-wise, the Papyrus VM will probably remain the same as it always has because to change it would require an extensive amount of retesting.

Syntactically, unless they want to break every scripted mod under the sun and rewrite many of their own scripts, they won't be bringing over Fallout 4's language enhancements and changes.