He has confirmed that he has been suffering from Parkinson's for the last 10 years and that it has now reached a stage where it impedes his live playing. As regards the studio recordings, who knows what was played by Richie Faulkner and what was Glenn Tipton's share, all they are saying now is that Glenn played "his parts", but not how much these parts amount in the overall picture. Faulkner has certainly - even live - taken a larger space than KK Downing ever had, who in essence was Priest's rhythm guitarist with a sizeable chunk of solos whenever the music called for a "dirtier break" than Tipton with his very structured, gentlemanly style could have naturally provided. KK with his Jimi Hendrix influence (in contrast, Tipton is more Clapton'esque) excelled at being the "gyrating guitar hero - noisy, bluesy & rock'n'roll". He kept Priest from sounding too clinical.
With all due respect to KK who was an integral part of classic Priest, I would doubt that he could cover all of Tipton's parts for the sheer necessary technique (and I've seen both dozens of times playing solos up close). While Tipton became evidently more analytical, even professoral in his playing over the years, KK didn't develop much, he's an intuitive devil-may-care attitude player, more Slash than - to mention a name rarely dropped in these quarters - Ritchie Blackmore. KK's on record for having himself stated in an interview that he admires Tipton's "overall fretboard dexterity which I fail to ever match" and it is true that KK tended to play solos in one or two scale positions only (the second position being generally the same one, only 12 frets higher) while Tipton's solos traverse the full length of the fretboard. It's a bit like Keith Richard saying that he could replace Mick Taylor. Something Keith would have never claimed.
