many of these points have already been discussed and explained here in the other relevant threads.

The tilt up panel is the same angle(s?) as we have now, this picture just gives a false perspective of it. 90 degrees does not make any sense however you look at it.
I have heard of no problems with 6000 swivel panel connections since the 6000 was launched, so any problems are likely to have been many years ago.

The tweeters are not blocked at all by the panel, and high frequencies are the directional ones subject to reflection off solid surfaces. By the time the crossover to the midrange speakers has occured, the minimal amount of grill behind the fold back panel is completely negligible compared to the wavelengths of the frequencies involved, so there is no blocking of sound at all.

I would have thought gigers would have been pleased to see the back of the raised grills that could be dented so easily through mishandling.

Since the tweeters are closer to the player than before in this arrangement, monitoring and clarity should theoretically be improved in comparison. It remains to be seen how successfully this has been implemented in practise. But from a theoretical acoustic viewpoint it is a very logical design and likely to be superior to what we have now provided that it has been balanced as successfully.

The Yamaha with the same physical arrangement was the psr6100 (then 6300) which Bill Norrie pointed out here, and which I thought of as soon as I walked into the demo, because both of us have owned that model in the past. This was 1986 I think.

The panel is much the same angle as the Genesys and the 6500 so I can see no problems there. My only concern is how far away the buttons are, and that can only be resolved by actually playing it and seeing if it suits you. We will have to see...