Sorry to bother you in English, but my German is to bad for writing all suggestions in German.
First of all my complements for the release of the new Stellwerke today they are very good. Though there are some things I noticed which are different in reality or are changed recent.
Venlo:
The Bu on the Viersen side of Venlo needs to be linked in a different way. Like this:

Beek-Elsloo
When I looked on Sporenplan, I noticed that there where some inactive switches near B-E which are still active in Stellwerksim:

Sittard
Sittard Hbf is a little bit to much fame, just call it Sittard.

The tracks 9 and 10 are all most correct, but they should be like this:

(Also I saw the tracks 6-8 aren't there, but I think you did that for saving space, right?

Timetable in general:
I saw most of the trains in South-Limburg are still using the 2008 timetable. At the moment the timetables of 2009 are active.

For example the 6900 series doesn't stop in Sittard on platform 20 but now uses platform 2a. At the moment I can't provide you with new data. I shall ask some friend of mine on some other forums.

I hope this feedback is useful for you.
Greetings from Sittard.
Peter