I flew some domestic Qantas flights recently that had the smaller sinks (similar to what we might see in a disabled stall). It really makes the lav seem more spacious, while not really taking away much comfort for washing hands. The size of the whole lav was about the same.
Gives a little more space for parents who need to change a child, someone who might want to change, and possibly give a disabled person space to navigate.

What you’re describing is the cabin flex option. (See AA’s A321NEOs.) It will become standard for all new A321s soon.

I wonder if A321XLR will get the staggered business class seats like those on SAS? Super Diamond on A321XLR would be too much space premium.

If there's an emphasis on all-aisle access, I think we'll end up with the VantageSolo: https://www.thompsonaero.com/seating-range/vantagesolo/

I'm actually more interested at what changes might come to the PE seats. The current ones are pretty industry standard overall, and the cabins are relatively small compared to both business and coach. Qantas tried "upgrading" their PE seat recently and have had quite a bit of negative feedback. Turns out it is all about pitch/leg room. I can only see thinner seat back padding for densification purposes.

No mention of new Flagship F seats. Curious to see if Longhaul F gets the boot.

Its sort of nice to invite passengers to gain insights on a new product. for the 789, my bet is that they keep the super diamond setup and add a door. Not sure why but doors seem to be the new rage.
Wouldn't it be extraordinary if they came up with a product like ANA's "the room". That seat would be a game changer for legacy airlines in this country. And since 789's are mostly long haul planes AA would leap into the upper realm of carries. Chances of that happening: <10%. As for the A321LR planes. Gosh, I hope none of my travels puts me on that plane. 4-5 hours on it, no problem. TATL or TPAC does not sound like fun from my home base here in LA. Im guessing these planes will be more east coast based and do hops along the eastern seaboard to europe. For once it would be nice to live in LA. In truth with dynamic award pricing, most legacy carriers are NOT rewarding loyalty. The only loyalty they are living by now is $$$$ and for that once my miles are virtually useless, I'll pick the best quality hard product for my hard earned money.

Shh.......they might add a new "rocking chair" fee

PE is what most intrigues me - either it essentially matches domestic first for pitch/width (which makes sense as the airlines align PremEco with domestic F), they go 5 abreast and there's a seat 2 away from the aisle, or they use a new layout of 2x2 slightly angled seats that provide the same legroom as 38" pitch, but spaced about 34-35" apart (think a similar angling as the 757 lie-flat seats but fitting the PremEco seat dimensions).