My biggest complaint about a journal-based interface is that it's impossible to remember when exactly you created a document if you created it a year ago. In other words, a journal is an excellent way to manage recent files (touched < 1 month ago), but completely unusable for anything you have on your hard drive that you haven't interacted with for a while. "There is this great photo I downloaded - probably the summer before last - or wait, maybe the summer before that - well, let's search the journal for all image documents, let's enter a 15-month range just to be on the safe side - oh wow, 4670 files, I wonder which of them is the one that I need?"
Fundamentally, there is no alternative to manually organizing information - tagging, well-designed folder hierarchies, informative file names. Until we invent strong AI, this will remain a task that the users simply have to learn to do on their own.