Layman Romanist Matthew Bellisario disagrees with "His Eminence" and states:
The only thing we have in common is using the name, Jesus Christ. ... I don't know what in the world the dear Cardinal was thinking when he said this. ... What is more ridiculous is that a Cardinal would think that all of this is a common point of reference of the gospel of Jesus Christ.(source)
I think Cardinal George has the better argument from Vatican II (after all, if Muslims worship the "same God" while explicitly denying the Trinity, how can Mormons really be left out of the big tent?). However, ignoring Vatican II, Bellisario has the better argument from reason. After all, it is (to use his word) "ridiculous" to suppose that the there is common ground with Mormons in the person of Christ, given that Mormons allege that Jesus was a created being. And while Mormon soteriology is closer to Roman soteriology than it is to Reformed soteriology, Mormons deny (among many other significant differences) that is “absolutely necessary for the salvation of every human creature to be subject to the Roman Pontiff” and consequently it appears that the Mormon gospel is different from the Roman gospel (which are both different from the gospel that Paul preached).
Thanks to Dr. James White for bringing the main article to my attention.