Some remarkably easy (in theory) steps in my view as well:

1) Much larger preparation area - if I can sort my items for screening (belt off, ipad out and phones etc in jacket pockets) and load a tray in 15 seconds I don't want to be stuck behind some eejit who is a) slow, and b) uses up / blocks an entire scanner in the process. If you're ready you go, if you're slow you're overtaken

2) Larger reclaim areas - I hate seeing my bag delayed on scanner belt because someone has used 3 trays and can't a) gather their items, and / or b) return their empty trays

3) Forget the swabbing etc on most lanes - send the bag (and person) to a segregated lane where they are told to check their own bag, remove items that could be causing issue etc and go through process again. Why waste resources on this when 90% of the flags (yes, I'm guesstimating) are people being forgetful, their time / labour is a much better way to sort it out.

The LHR T5 set-up with 2 people loading trays at same time is a step in the right direction on point 1 vs. T1 and many other airports. LCY has tried a couple of things at least, with separate shoe scanners and (sometimes) separate staff for searches if someone trips the metal detector.

I'm now off to indulge in pontificating on other inconveniences in my life such as people who insist on only taking their oyster card out after they've stepped onto a bus (as if the 5 minutes at the bus stop was without any real expectation of a bus ever arriving). My blood pressure will return to normal in about 45 minutes

(and even further OT, kudos to a particularly animated queue manager at T1 security the other day, the guy was dancing around continually directing people to the shortest queues - such an unusual display of proactive management that he must be new. He even released us from FastTrack given it was clear we'd be so much slower in that queue)