The rear of the new renderings has a resemblance to the current 2-series, it must be a new "design language"
I would prefer the rear to be somewhat similar to the current 6-series, it looks great.
I also hope the new 5-series will be significantly lighter (around 1650kg with a 6-cylinder engine). I drove all kinds of 5-series cars including M5 and there is so much power wasted to move that weight, power that could be used to generate additional shove in the back in a lighter car.