The information in this article has been transcribed from the Joomla! User eXperience (JUX) Webinar. This was a webinar upload in early June of 2012, in which Kyle Ledbetter (lead of the Joomla JUX project) discusses upcoming changes in Joomla 3.0
General thoughts on Joomla 3.0 and Mootools
Joomla 3.0 will now ship with jquery in the core because bootstrap was designed to work with it and the goal is to get all of main core functions working over on jquery. It will also ship with mootools for compatibility reasons but we're trying to get everything on the same page and I think a lot of developers are going to be excited about this because a large amount of them are already loading jquery on their own because it's easier to develop with, it has more rapid deployment. So it's really a chance to be a great equalizer and get us all on the same page.
What is the status of Mootools going forward?
How is the transition from Mootools to jQuery going to be, are they going to live together?
Jquery and mootools already live together all the time in Joomla 2.5. The focus is now going to move to jquery. So a lot of developers will probably update their components to primarily use jquery , but a lot of them honestly are already doing that, but there is a select few that really prefer mootools.
Joomla Community Google+ Hangout #3
June 3rd, 2014
Thank you @RustyJoomla for letting me speak on the Joomla Community Google+ Hangout!