I think the real issue is one of timing. As you and I know Knopfler/Fingerstyle guitar is very precise and demanding, the slightest of errors can leave you looking a bit silly. That's what I've sensed from much of marks recent playing. It will be interesting to see what happens during the rest of the tour because it could just be 'rust' rather than age that we're picking up on.
Also note that on TR, for instance, he uses a much more overdriven guitar sound than previously. That makes things sound much more fluid and covers up moments of "imprecision". Same with Once Upon A Time.
Some may call it cheating, but I actually admire Mark for adjusting to reality and being able to make things work nonetheless. It would not work on Sultans, I think. It has and requires too many "twiddly bits" to be a proper version, and with a distorted sound it would sounds mushy.