First do not panic, as your heard Google is doing some cleaning up of Motorola. One of the cleanups is duplication between tool sin AOSP and Motorola. MotoDevStudio For Android is not dead as the plugin stuff got opensource and donated to AOSP.
However, they had to stop the duplication so there is not a new download if you did not get it recently. There are some directions over at Motorola Developer Resources in how to build the plugins however.
As far as I know its being merged into ADT along with the other big change of using Gradle as the build script tool-groovy language based instead of Apache ANT. What that probably means its that we will see an alpha build of the ADT as we get to preview the 22 version of Android Tools before Google IO 2013.
Thus for right now its a bit of a pain but Google had to act as if the MotoDevStudio downloads were still accessible than there would be all these support questions in the forums which would take away from the other developer support questions they need to answer.. Thus, in summary before the next release of Android Tools and the ADT to get the same MotoDevStudio For Android feature set you will have to click on the link above and than click on the link under Core plugins and follow the build instructions to get those plugins to install in Eclipse.