For me it isn't so much an issue to deal with them, but that it would distort the narrative for me to do so. How might tactics and technology need to change to respond to the possibility of such a fighter? At 11th level it looks like the CM/SS Battlemaster Archer using Hand Xbox can choose four of the following attacks per turn (3 actions + 1 bonus action)
1d6 + 5
1d6 + 15 (-5)
1d6 + 1d10 +5
1d6 + 1d10 + 15 (-5)
They'll have 5 superiority dice so that is an exhaustible resource. They'll have AC 17, +11 to hit, and +5 to initiative given 20 Dex. A level 6 Battlemaster level 5 Swashbuckler duelist can
probably defeat them as, with similar stats they can have AC 19, +9 to hit, and +12 or so initiative through taking Alert. They can't Riposte and trigger their Sneak Attack damage twice, but they can rule out the +10/-5 attacks through Uncanny Dodge which will punish "spikey" DPS. It depends very much on who fails what saves against combat superiority maneuvers, and how the out-of-combat skills play out. Battlemaster/Swashbuckler Stealth likely beats Archer's Passive Perception whatever they roll.
I point this out to say that the archer is a very narrow character. Strong in an outdoors clear area with 120' sight in all directions. Weaker in other situations such as a winding corridor in a dungeon. Attending to detail then is probably how one avoids distorting ones narrative around them.
It's strong, but again I wonder if the devil in in the details? Warlock Dragoons could easily be a thing, but in a dungeon?
I think the PAM GWS guy could be looking for crits to balance things out. Say taking Half Orc and Champion to double down on that. Then with the heaviest possible armor to compensate for the lack of shield and need to stand toe-to-toe.
Yup. For me the biggest issue with CM/SS is actually the obviating of cover. It makes a non-narrative-distorting combat harder to achieve.
They go from +11 to +6. For me this more reveals an issue with low ACs in the MM than anything else. The MM is set to "easy" difficulty so far as I can see. Dial that up a little and dropping to +6 makes it much less of a gimme. Again, it's ignoring cover that really concerns me.
I part agree with this. I'd just point out that the rogue has narrative power: solid abilities that allow players to advance the narrative in their preferred direction. It's not all combat
Well, the Wood Elf Monk at 11th level with Mobile can go for moving say 65', with +9 to hit, AC 18 or so, +5 to Init
close 30'
1d8 + 5 (save vs stun)
1d8 + 5 (save vs stun)
1d8 + 5 (save vs prone)
1d8 + 5 (save vs prone)
and then retreat to 35'
So that isn't horrible. Once the CM/SS fighter is out of their 5 superiority dice, the Monk's 11 ki makes them look a bit better. My personal fix is that a short rest is 6 hours, and a long rest 2 days. So there's that

To close from 120' (worst case), the Monk could move, dash, dodge. In that situation the CM/SS archer can't really throw in 10/-5s. Or maybe on one or two attacks with precision strike but then - Deflect Missiles.
Until you run out of spell slots and Druid transforms back to human shedding all damage...
The most broken builds don't seem to me hugely above the others. They're strong. They're a poser. They're not far from fine.