Cant do it like that because each newer version could break functionality and themes depend on modules in which they where written for.
Sometimes you can upgrade modules in a theme and it has no dire results and other times the theme just will not run.

If you have the modules included with the themes it makes the theme much more bloated when it is released. The point when you release it is to make the file size as small as possible.
OTS2 solved this by placing all theme modules in the module folder for all themes to use requiring only 1 existence needed on the hard drive.

Just a side note andymon has been working on all the xmodules and they are very good to use in a newer litestep theme.
So I'd suggest starting with those modules.
Be aware that there are modules he released using xpaintclass.dll and IMHO these modules are really for ppl who want to make imageless themes.

Just read the docs that come with the modules and see if it is an XPC = xpaintclass module.

So all in all stay with the newer modules because they will have more features you might want.