Comment by panick21_
The big issue with S/X was that they were not luxury enough, in terms of performance they were fine. So the redesign was mostly needed in terms of interior quality, materials and so on. Not that crazy expensive and something all other car companies manage to do.
I see it differently - they needed to redesign everything except the power train. I.e. in addition to the interior, externally it should have been looking way upscale from 3/Y. Giving that their design language is already almost 2 decades old, they needed (and actually would still need it for 3/Y max 5 years down the road) to have a full redesign for S/X similar to how BMW did with 2002 7-series trickling down that design into 2004 5-series and 2006 3-series (or like Mercedes did with S-class in 1996 and trickling down that to E and C later)