Do you want extra functionality added to the new slider or the option of having the old slider put back as a switch-able alternative? The latter does have lots of issues, which was why it was removed, that would need to be addressed if it were included again.
Also, I did look at the code: http://tympanus.net/codrops/2012/03/15/parallax-content-slider-with-css3-and-jquery/ and have just looked at the license for the site upon which it was hosted: http://tympanus.net/codrops/licensing/ - and need to be sure that the theme is compliant, as "You are not allowed to take our work "as-is” and sell it, redistribute or re-publish it, or sell "pluginized” versions of it." but "If you plan to create free WordPress, jQuery, Joomla, etc. plugins out of our scripts, please credit us in a fair way and link to the respective article on Codrops." so would need to be sure that all of the theme complied with these terms.
Of note is the line: "that most of the tutorials and resources are experimental and not ready for production, but made for inspiration and demonstration purpose only." therefore would indicate a non-production ready state for versions of Essential that use it."
Therefore the current version only incorporates the stable Bootstrap 2.3.2 version of the carousel.
