German mag "buffed.de" interviewed several Bioware guys. Scroll down to the video. It's in english with german subtitles.
Richard Vogel (Executive Producer) said that servers can have 80k-100k players (jump to time index 19:30).
http://www.buffed.de/buffedde-Brands...cklern-858928/
He later says that they put 200,000 bots on one server to check their limits. Many asked how many players a server can have - here is your answer.
How many they will allow before they wave the "full" flag is an entirely different story.