Why's that controversial? Julia Goerges's serve is one of the most (if not the most) effortless serve in the history of WTA. According to WTA's own speed guns, only Sabine Lisicki and the William sisters have hit harder than Goerges on the main draw (Not counting the likes of Goergina Garcia Perez and Brenda Schultz McCarty's exploits elsewhere).Possibly controversial choices but I always loved to watch the serves of both Giorgi and Goerges. The way Giorgi's arm goes up so quickly and hovers is simultaneously elegant and threatening, and I just find the elasticity of Goerges' service motion really fun. I could watch both of them ace or double fault all day, which is/was often what their matches are/were like anyway.
Yet look at Julia's body: Very ordinary. She's not tall (like most of the big babes and ace queens who have angle advantage over the rest), she's not broad (like Serena or Sabine Lisicki or Ash Barty whose stronger core provides more stable support and easier body weight transfer into their shots). Yet Julia casually produces 124+ mp/h monster serves as if they are nothing. No sweat, no heavy breath, no noise. Just effortless extraordinary timing. I suspect it's down to the elasticity of her joints (flexibility). Similar to Andy Roddick on the men's side.