1) It would be neat if you could have a "default sector" preference option--it would really help out those who like to have their journal be completely friends-only, for example.
2) The ability to adjust the date/time on journal posts? And on modifying them, perhaps?
3) An option which takes a greatly lower priority for me, but would still be cool: if, from within the "compose" window, you could set what memory groups the post would go into, and--after submitting--have it both appear on the journal, and be put into the respective memory categories.
4) Lastly, purely for those who aren't familiar with HTML, perhaps a WYSIWYG style-setting options? EG, you press cmd+i, type text in italics (with it appearing italics on screen), and press it again to go back to normal text. The idea being that, although Joe Schmoe End User sees italic text, iJournal actually submits the text with the (i* and (/i* around said text, for example. Not a high priority for me, because I know HTML. ;)
Anyhoo, my few coffee beans worth. :)