They’ve already been pretty optimized, and don’t load and use things you don’t use for almost all cases.
The theme support plugin adds all the shortcodes, but they are not fully loaded until they are actually used. And these would only slow down the host a tiny bit, and have almost no measurable effect on load time. Same for Xtreme Plus shortcodes.
The only significant script loaded by Xtreme Plus is the smart menus, and only then if you check the use smart menus option. In my tests, they actually seem to load faster than the default menus.
I will try some of my own test to see if I can detect any specifics for Weaver’s plugins.