It was obvious to me as soon as I saw the oscilloscope that there is a capacitive glass touch sensor on top of the LCD screen same as all other oscilloscopes with touch or any tablet. The screen and capacitive glass touch sensor are two separate components.
It's not always necessary to use oversized touch screen panel. In handheld devices such as a tablet that has its whole top surface covered by glass, a wide bezel around the LCD is necessary, otherwise user can't hold the device without obscuring part of the picture by finger. So in that applications it's natural to use oversized touch screen. But when the screen is only a part of the front panel composition, the touch sensor panel can be of the same size as the LCD panel. Some touch sensitivity impairments in the edge areas can be worked around by don't placing GUI control elements there. That designs are also known. As for the oscilloscopes, it seems the oversized glass is a matter of fashion. With that trick, on the ad leaflets, the screen looks larger than it actually is. Never mind though.
8bit is just 256 so easy to fit 1:1 on any screen.
In DS/MSO1000Z series (8 bits), the LCD has 480 pixels in the Y direction. One waveform point takes 4 pixels (2x2). So only 200 ADC levels can be displayed in the drawing area, the rest 80 pixels are consumed by the top/bottom GUI elements. A waveform of pp amplitude greater than 200 levels always looks clipped. That was widely discussed here over the years. What I'm trying to say is that if similar approach is taken in the new model, one associated inconvenience is that it's not always easy for user to find out if the waveform is actually clipped because the amplitude has already reached full-scale ADC range or it's only visually clipped and there will be no clipping in the waveform data downloaded with SCPI commands. The scope does not provide related indication.
Besides, there are more interesting things, which are related to ENOB and stuff that is related to the analog circuitry. I'm hoping that will be revealed here soon. You can use 1000 bits ADC but with mismatching analog part the actual resolution will be not so great. It also affects the math function results such as FFT. In my opinion, Rigol can be differentiated by its FFT implementation. It's not so nice looking as that of the competitors, but it's fair because it does not provide user with false sense of confidence. No data or evident garbage is better than not reliable data that looks plausible. Economy-class analog part and a 12-bit ADC. An interesting combination.