Translations in two directions (german articles -> english ; english articles -> german) aren't feasible in the long run. You've already seen that in proc magazine.
I would prefer a bilingual magazine. German authors who are able to write in English are kindly asked to submit their articles in two languages.
Other could transmit their articles in their only language.
Then we had 1. german only, 2. english only, and 3. bilingual articles in the magazine.
However, this concept is not capable of a majority in either the executive board or the general assembly. So far...