There are no plans to drop the "prebuilt example of what is possible with Core", TinyCore.iso.
The Core Project will continue to offer both isos MicroCore as well as TinyCore.
The change in 4.2 is to emphasize that our project is not dictating your desktop. Nor does one have a add on their preferred desktop. Using extensions choosing a desktop is just as easy as choosing a browser and without the extra bloat of unused or unwanted software.
I knew from the beginning, that if I offered a tiny CLI distro that it would not get much attention, but a tiny GUI Desktop would.
As users get comfortable using extensions, which is an absolute requirement in all cases, Such extension use is easily extendable to the the desktop GUI. I still get complaints about the default window manager. CorePlus showcases several Desktops, one of which the user may prefer.
The whole concept and philosopy of Core is Choice based on a tiny foundation.
I repeat TinyCore iso is not going away. It will continue to be offered as a working example of a very tiny GUI desktop.
Users may continue to use TinyCore as their main desktop from which to build upon.
4.2 moves the Core Project to a common foundation, which is easier to support both code and forums.