I'd like more custom facing options in Acrobat. This is extremely useful for the new giant Surface Studio device (or any large monitors). For instance, in Foxit Reader, you can set up to display 4 pages side by side in continuous mode, resulting in 8 pages in a single view (shown below). This is possible with the 28 inch Surface Studio. The same function also exists in Word 2016 where you can have 8 pages displayed and edited in a single view. This function is extremely useful for productivity (combined with the touch and pen capability of the device).
It would also be nice to improve the touch and pen capability (by copying its own Acrobat/Adobe Reader mobile apps or the Xodo app in the store). For example, a floating menu displaying commenting options would be nice after using touch to select a word or a sentence. Currently, there are not many options to adjust the pen settings. No stroke eraser, no pressure sensitivity, and no easy way to turn off touch when selecting different tools.