DS songs, especially MFN and SOS are like Marks signatures and I think it's great that John doesn't want to copy them; if he just copied Mark he would be a like a tribute band (or a part of). He puts his own stamp on them and that at least shows he has put some effort into trying out new arrangments.
Exactly, that special MFN riff and the twiddly notes SOS solo are the very MKs signatures.
These parts played very very important roles in these 2 songs, which thanks to them became milestones in DS (or should we say MK) history. The riff and twiddly bits are not just "another solo" from I don't know, Expresso love or Ride across the river. You can change and vary and make up solos in those kind of songs almost as you like, but imho you can't change such a significant part of MFN or SOS.
To me, any MFN or SOS without them is just another cover by a tribute band.
