The loss of power in his voice doesn't bother me much, sure, I wonder how he is going to cope but it applies to over 90% of the vocalists when aging, although it is admittedly dramatic with Phil. I concur that some songs can benefit from a softer approach, although not MoC imo, the dynamic of the song is based in that octave jump. It could work for softer songs, you mentioned Ripples I could add FYFM,
I guess it is how his voice transformed that rubs me the wrong way, it's just too nasal for me.
It is more nasal and I am not exactly sure why. Age sometimes deepens the voice, which often adds a really nice richness to compensate for the loss of range. Phil's voice has changed in tone in multiple ways over time. It was lighter and initially lacked heft early on, then became stronger and lost some of that light touch, it then became warmer, and then became lighter and a bit more nasally as you mention.
There are a number of songs that might fit his voice now. Some would be great to hear - e.g., Blood On the Rooftops, Inside and Out, the full Cinema Show (the high bits are falsetto). We'll have to see what the final setlist looks like.