First of all: AWESOME PIECE OF WORK!
Appreciate it very much!
But ... (Some people are never satisfied with what they get :-))
Could you make the comment columns of the other language files available as well? Thus we could use them for taking notes of the translation status (e.g. please translate, suggestion, approved, original value changed, etc.) and filter on them as well.
Another great thing would be, if you could take a snapshot of the neutral resx file, each time we use the tool. This snapshot could then be used to show changes in the neutral resx since last time, we used the tool.
Hope you get what I mean. I could probably explain it little better if I could do it in german!