pb,
No worries, and certainly no need to apologise. Thank you for your words.
The way the aircraft fly at the moment is also a function of out-of-date SIDs and STARs. You mention the MID route. The published route itself goes too close to the OCK stack for continuous climb. Current rules say that as soon as 4000ft is passed, aircraft can be vectored off the route, so the variation in the turn is symptomatic of the different climb rates. All this requires ATC interaction, and radio transmissions, which increases workload.
Concentration v dispersion is an exhausting debate, not least because upon examining many complaints/comments you see that many people stand on different sides of the spectrum depending upon how they are affected. Out there on Twitter there are those who complain about concentration on departure tracks, yet who also complain about arrivals taking 'random' routes from stacks to the final approach track. Or some who complain about concentration regarding what they see as arrivals following the same routes from stack to final approach, and yet complain about departures being vectored off the SID route once through 4000ft which creates dispersion.
(not saying this is you in any way, pb!)
It's a difficult debate, and one that involves many parties (Airports, ATC, CAA, Airlines, Manufacturers). With the advent of flight tracking apps and sites, and the potential for misunderstanding of the data that is presented, it's a debate that is only going to get more difficult: Witness the fact that some are complaining about Stansted and Luton inbounds routing over LHR at 15000ft, claiming that this has never, ever happened before 2015. Or that noise complaints are being filed on aircraft transiting over London on their way from Dubai to New York at 37000ft.