With the 0.63 draft all web services get a new extension parameter. This makes API less readable and really ugly.
Do we really need the flexiibility at this level? Some pseudo code

before:
return _objSvc.getAllowableActions(_repositoryId, id);

after:
Holder<CmisAllowableActionsType> holder = new Holder<CmisAllowableActionsType>();
_objSvc.getAllowableActions(_repositoryId, id, null, holder);
return holder.value;

This requires three lines instead of one. It is no longer clear what the return value is and what parameters have what purpose. We have methods taking three holders, etc. I liked the CMIS API for its clarity and simplicity but now I fear we are far away from this. This seems to affect every function in the web service.

Do we really need this and want to pay this price?