In LR3, one could skip a level in selecting which keywords are exported. For example in the hierarchy A, B, C (where A is top parent) one could set A=Include on export, B=Do not include on Export + Export Containing, and C=Include on Export + Export Containing. In this way, on a photo with only keyword "C", on export we'd have A and C but not B.
In LR4 all my LR3 keywords that had this pattern were changed during catalog conversion and I can no longer set this pattern. Turning off "Include on Export" now turns off "Export Containing" and "Export Synonyms" rather than leaving them alone as in LR3.
This is a HUGE problem for me as I have my entire keyword hierarchy (over 3,000 KW's) designed to allow skipping levels. In addition, I have cases where the actual Keyword is for my workflow and convience but but the synonym is what I want exported (not the actual KW) which I can also no longer seem to do.