if not, i would chose your first proposition
hope it helps

Just sounds more fluent!

I suspect that the German is actually a back translation from the English. "Wealth of functionality" is a frequently used term in descriptions of various s/w packages. See the following (from some 500+ hits)

Although Adobe Portable Document Format was introduced in 1991, the architecture
still holds a wealth of untapped functionality. PDF was clearly designed for ...
www.planetpdf.com/binthing~webpageid,622.htm

Its many application programming interfaces (APIs) provide a wealth of functionality
for all aspects of application and system-level programming. Although ...
www.amazon.com/exec/obidos/tg/stores/detail/-/books/0201715... reviews/ref=pm_dp_ln_b_6/

This new DynLayer has a wealth of functionality that wasn't present in DynAPI 1. You can now create and delete layers on the fly at any time by making a new ...
www.dansteinman.com/dynapi/dynapi2/docs/api/core.DynLayer.h...

Communications technologies like audio and video conferencing have a new wealth of functionality.
www.admiral-group.com/voice_and_data/applications.htm

Unigraphics is a high-end 3D CAD system from Unigraphics Solutions that provides
a wealth of functionality that midrange systems don t match. It has a number ...
www.ugsolutions.com/publications/articles/cadalyst_0600/

...functionalities would be used in the context of ways of functioning and is the direct translation.
...functions would be used in the simple context as in operations, for instance