Closer subs - Substitutes would walk off nearest touchline rather than to technical area
I can see problems with players in full playing kit wandering around the outside of the pitch... not sure this is a good idea.
Yep. I run the line at my son's game most weekend. My ABSOLUTE pet peeve is subs, or recently subbed players walking up and down the touchine without their bib or rainjacket. It makes offside much harder to judge. Admittedly PL assistant refs will have better eyesight and training than me and a pro is unlikely to stand still picking their nose while they try and remember where they left their water, but nonetheless it could cause issues. Injuries are slightly different as the injured player is normally accompanied.