The package summary and description for python3 and python3-base are nearly the
same (except minor wording changes), which makes them not-too-helpful if
someone wants to know the difference between python3 and python3-base.

I'd expect a short explanation in the description that explains what each
package contains, for example:

(python3-base)
    This package contains the python3 interpreter and the most used 
    python3 modules.

(python3)
    This package contains some additional python3 modules.

Please adjust those texts as needed - you know the package content much better
than I do and hopefully can come up with something better than "most used" and
"additional" ;-)

Also, a different summary might be a nice idea.