Same here, I was wondering why that function doesn't work anymore. I don't use BibTeX (it effed up the special characters in my bibliography, e. g. umlaute and it took me an hour to clean up my bib file). Instead, I have set the proper TextMate project variable and it did work before with the same project.
But until recently, I could use only escape to shuffle through suitable entries of the bibliography without using BibDesk at all. I definitely prefer using escape over alt + escape, so if there is any way to get the old functionality back?
Here's another vote against removing the old escape-only command ;-)
Max