I think the main point is, why hasn't he DIRECTED any of those small-scale films he talked about. Producing and co-exec'ing ain't like lending YOUR own personal vision to something. It's been said he's quite a nervous and shy person, so maybe the thought of something quite intimate and small just became to big for him to accomplish. Guess we'll never know.
I wasn't joking about the Howard the Duck remark; that's what someone actually said in the documentary.
As for Star Wars, I wonder why he feels the need to return to it and to waste time tinkering on what obviously isn't broken. He had sixteen years to write the screenplay to TPM and the end result has largely been viewed as a failure. Yes, those movies made money but that name brand is clearly a powerful one. That gullible and overly-sentimental fan base (IMO) and a highly, highly aggressive hype machine leads to financial success but the end result was three critical failures and I'm sure most of the fans dislike those films, as well; or maybe not(?). I suppose he'll revisit the prequels sometime up the road. Unless he got those "right" the first time around.