Yes, the 2020 number means nothing, nothing has changed in workflows on beta, there is no page flipped in the book, no ticks made. Its just normal as usual, a point release with whatever they managed to scoop into the build before the compile window closed, and this will continue to progress like that, just like it has been for some time already.
Right there is no plans to support any further legacy maps, the reason is logic of course.
OSL + Arnold shaders are superior in both flexibility and what you can actually do, and both shader standards will be supported on the GPU which is a significant deal.
The old legacy c++ shaders needs a lot of work and there are many, we already have superior noises via OSL than the noise maps that comes with max can ever hope to deliver as well.
Bercon noise needs recompiles and is also a legacy construct, we can build noises impossible to build with bercon maps, in OSL and we dont need to worry about having the latest Bercon.dll for the most recent max version.
With 2020 you also got simple tiles. OSL which effectivly takes the coomercial floor generator out of the image in a snap.
This is also why I developed a workflow around an OSL shader I wrote that is called Procedural Color which more or less takes Forest Color from Itoo out of the equation for vegetation, and I dont have to speculate over old shading standard shader hooks any more.
OSL can be ported via materialX to maya, houdini, c4d, katana, the old legacy maps are stone cold on that account.