Oh yeah - Our "Premium" support was without a clue and after two days have been no help in regards to this - other than to revert to the previous version (which is an ordeal to say the least)
However, looks like we fixed the issue and this is *definitely* a functionality difference between 7.7 and 8. It turns out that the value placed in the Transport Attribute field must be all lowercase (this is new behavior). We reverted back to our original query filter and tested with the lowercase transport entry and it worked properly. Also, we discovered another change to the "Test" query button in the LDAP routing section - it limits the query to 1000 meaning that the test can give you meaningless results if you only have a few entries that have the attribute set in a large LDAP directory as we do - this is different behavior from 7 which returned every entry matching the criteria. Symantec claims no changes to LDAP - I beg to differ.
Good stuff. Anyway, maybe this will help someone else out there...