1. You do not have to use M1, so why bother?
There may be someone else who finds it useful so why remove something that has been working since?
Plus, SysPrep may rely on that, dunno (never used that myself so I wouldn't know)
2. The size increase by using the less memory-dependent lower compression seems to be negligible, unless you were down to single digit MBs already...
If you also include Windows updates, then you will hit the limit eventually, as these grow a bit each month.
Also, WPI could easily been "exiled" on a second DVD or a network drive, if needed.
True, breaks the completely unattended installation but you could use a second drive if you had etc.
3. Better by what?
Faster?
Yes.
Fragmenting the drive less?
No.
Also, that is exactly what the Finisher does, cleaning up the archives afterwards...
4. The new auto-updater for the DriverPacks included in BASE kinda makes this a no-brainer.
There is virtually no difference for the user if they have got all packs at least once.
If it auto-DLs one pack or a handful, doesn't matter.