I don't have mine yet, but it's disappointing to hear that the cushions are moulded rather than softer material causing this issue. As many folks have mentioned, the throne costs as much as a 1:1 chair so it would have been good to see HT go the extra mile & use soft goods for the cushioned parts. QMX managed it with their command chair (although admittedly on a less complex shape).
I suppose it at least removes any concerns over material disintegration issue...
I don't think a softer material would have helped, as the figure still wouldn't be heavy enough to sink into it like a real person would. And I can't really get Kirk to sink much into his chair either. They probably would have needed to do some kind of swap out piece that was specially made for the Emperor to sit in.