Mark and John are a DS reunion per se.
I always thought exactly the same. To me, DS is Mark and John, and only Mark and John.
Therefore, the 2002 gigs were a DS reunion (at least a part of the gigs), but not called this way for the reasons you said.
So again, I can't see why a Mark/John reunion in the future would be called a DS reunion.
And it's the paradox I was talking about :
during DS days, fans were going to concerts to see mainly Mark and John, no matter who was the 2nd guitarist or the drummer
during solo days, fans are going to see Mark, with John McCusker, Richard, Glenn, etc...and would be disapointed if there would be members changes...
strange feeling isn't it ?