Description: This code:
$Conditions['exists'] = "(boolean)ListPages(FixGlob(\$condparm, '$1*.$2'))";
appears to maintain current "exists" functionality while also allowing wildcards in the argument.
There would be a slight performance penalty since it would no longer make use of the $PageExistsCache. In 99% of cases this would be negligible, but it could have an impact on a page with a large number of these conditionals (such as in a pagelist).