Spencer is probably a nice person, and anyone who's seen clips, over the years, of him playing with Alain's group, or knows that he's a pianist and a songwriter would know that he's got talent as a multi-instrumentalist. However, anyone who would like Spencer to be Morrissey's drummer again is purely seeing things through nostalgic lenses, and clearly has no general appreciation for what percussion can bring to a song. The Matt Walker - Morrissey era, the drums on the recordings - patterns, nuances....have never sounded better, louder, or bigger. Morrissey at this stage in his career would go with a more accomplished drummer anyway, someone who can easily shape the rhythm in different ways (almost as if they too are composing the song) because of all their experience in music, not just as a time-keeper.
Matt W. is ACE! He's probably one of the top 20 drumming-minds in the world, I'm not kidding. Youtube 'Hated for Loving Kettering OH' (I LOVE MORRISSEY's post) - anyone who really knows that song.....you will see how much change and dynamics he brings.
Btw, Matt's played live with Garbage for something like 15 years now, simultaneously as he was recording/playing live in Morrissey's band. Drummers can do that as most are freelance and not tethered to one specific act.