@All: I am not a CM, but I have touched upon this general topic before. Roleplayers are a minority, even on roleplaying realms (both Classic and BfA ones). It was very close that there would not even be a RP-PvP realm at all. To put it quite simply, there are not enough roleplayers to support multiple RP realms.
German speaking player base is of significant size (my last calculation put it somewhere close to 230 000 on BfA side, which meant more than 25% of my EU size calculation). However, out of that number only a small portion play on Die Aldor and the other German RP realms are probably best described as tiny in comparison to it. Argent Dawn is significantly larger than Die Aldor and despite that fact, Hydraxian Waterlords struggles to maintain “Medium” status… and Zandalar Tribe, while a nice realm, does not have much apparent RP left.
Classic, by my best estimate currently has less than 56 000 remaining players on the German realms total at prime time peak and judging by Blizzard decisions and already published blue posts, the number is still decreasing… 
Roleplayers do not form 15% of the total player base on BfA side (in fact, the probable number is under 3%) and even at 15%… 56 000… equals perhaps 8 400 + a few who are not playing… and to maintain a realm at reasonable activlty level… takes about 16 000. Theorhetically, Blizzard probably could launch a single German RP realm, BUT it would likely max out at “Medium” or even “Medium”-“Low” depending on time of day.
I am not saying it can not happen, but I find it highly improbable, to be 100% honest. Sorry! 