Earlier, you noted that 3.2 improvements would NOT apply if carrying DisplayPort over USB-C.
Yes - USB 3.2 doesn't increase the speed per lane, its 10Gbps and 20Gbps modes work by using
all 4 high-speed data pairs in a USB-C cable (giving 2 5Gbps g1 or 10Gbps g2 lanes), whereas USB3.1 only ever uses 2 pairs. All 4 pairs for USB = 0 pairs for DisplayPort. 3.2 will fall back to 3.1 speeds if only 2 pairs are available, or USB 2.0 speed if there are none (USB-C has separate wires for USB2.0 fallback) ...
If this is so, when 3.2 is released, will there be any changes to the signaling of the DP stream where it allows 4k60hz to NOT occupy all of the SuperSpeed lanes (and enabling more than 2.0 data speeds with 4k/60)?
No, the new 3.2 speeds will always need all 4 high-speed pairs (doubtless 3.2 will be followed by a shiny new version that gets more data per lane).
What will improve things is actual support for DisplayPort 1.3/1.4 which ups the DisplayPort data rate, so you could have a 4k60Hz display using just two pairs, allowing USB3.1 speeds, and 5k with all 4 pairs (rather than needing Thunderbolt). The USB-C/DisplayPort alt mode standard
allows for DP 1.3/1.4 but as far as I know no current computer actually implements 1.4-over-USB-C (and Intel only support 1.2 in their CPUs and controllers), and DP1.4 monitors are fairly rare.
However, that's still going to take at least half of USB-Cs high-speed data pairs, so while it might make USB-C docks more useful, it won't help USB 3.2.
Thunderbolt is different because it bundles everything, including DisplayPort data into a single
thunderbolt signal that then uses the maximum available bandwidth - much more efficient than physically allocating protocols to wires. Downside - each peripheral needs a full-blown Thunderbolt controller to unbundle the signals. However, it still only supports DP1.2 - those 5k Thunderbolt displays work by bundling two DP1.2 streams into the thunderbolt signal and splitting them again in the display.
Honestly, though, with 5k and 8k displays sucking up huge amounts of bandwidth, I wonder what the point is of combining display interfaces with other I/O - and PC workstations/gaming rigs (as used by many people who want high-end monitors) still use PCIe graphics cards with hard-wired DisplayPort or HDMI sockets.