I also reckon that the patch definitely improves, but there's still something slightly wrong even in Mint-X. Compare the "old" and "patch" look of gedit:
From the above examples, you can see that the patch does not quite restore the pre-gtk3-upgrade situation. Shouldn't the text background be plain white? Also, you can notice that the toolbars have been slightly affected.
I see this with Mint-X as well as Mint-X-Metal.





