I like the idea of increasing maximum block size without hard-fork/actually increase block size (from legacy nodes perspective), but besides that i don't see much advantage of your proposal since :
1. Complicate way/method, even though mostly only developer who feel it
2. Introducing another address standard which complicate UI/UX and probably confuse some people. Edit : instead of introduce new address prefixes/format, why don't you use use next witness version (bc1p)
3. Unlike SegWit which also solve malleability transaction, your idea don't have any
I don't think we'll ever see another softfork similar to segwit. We somehow got segwit in and it seems to be working, but some still question that it is safe and always will (and have good arguments to think so)
The amount of controversy needed to get segwit in was incredibly insane. You would need to have a package of updates so good that it can be done again, and perhaps not without another round of transaction backlog either organic or spammed again.
I think no matter how good ideas are, unless bitcoin is pushed to its limits and this idea is presented as an acceptable solution by many relevant parties, we will not see further updates, definitely coming by way of hardfork, and very doubtfully by controversial softforks.
It naturally all depends on how contentious any new proposed fork is seen as. The next softfork is likely to be Schnorr, unless I'm mistaken. The only way I could see that one becoming controversial is if someone starts a bandwagon for BLS instead and a rift forms in the community again. But then, knowing this community, that's a distinct possibility, heh.
Provided it doesn't become some polarised imbroglio like last time, it should hopefully be fairly straightforward.
A bit off-topic, but those who might start the bandwagon now currently have their own
Besides AFAIK, Schnorr verification time is slightly faster than current ECDSA while BLS is slower than both of them and people shouldn't have much decentralization concern.