Some of the (imo) important issues have *not* been validated by the core defs. So besides the BPMN2 things there is more. 4.4 is indeed postponed, but afaik JBPM will not release sp's anymore. Instead, the BPMN2 issues would slip to a 4.5 release. So instead of putting additional effort in 4.3SP1, I'd put that time in 4.4.
Informally I've read somewhere that 4.4 is due mid april now. Ofcourse you are always free to create your own release ;-)