If the scrum half lifts the ball its out IMO Ruck definition!! ball is no longer on the ground !!!!
But WADR Womble, if the SH has had to go in deep, as we all see occasionally , say with him being on one knee or leaning well forward.......then your saying the defence can leave their blocks as soon as it is 3 inches off the ground?
Similarly we all now see players in the ruck manouvering the ball off the ground .... For the sake of description let's call it nicely 'presented' ....... For the scrum half to collect (ignoring discussion on that aspect for the moment) then it too is off the ground, meaning out the blocks is OK in these scenarios also?!?
This not seen or allowed, there would simply be uproar/chaos if it was. So whilst i understand your point, it makes much more sense to
A) allow the manouvering,
B) wait for it to exit the 2D perimeter
C) keep defences in the blocks for a fraction of a second longer
SH would have no benefit for deliberate procrastination, its in their interests to exit it quickly (other than drop goal set up, but if that was the objective them they'd simply leave the ball in the ruck a while longer , so I'm discounting that motive)
I see no value in having different "out of the blocks" timings, dependant on whether no's 5, 1, or 9 has the ball raised off the floor...simplify not overly complicate interpretation IMO