Via the Meta-Data system for journal entries, allow users to specify a "category" for each journal entry. Then allow the filtering of lastn by category, just as the friends page can be filtered by friends group.
As an added bonus, allow users to define a default category to automatically filter their lastn page by.
This will allow me to distinguish between a "poetic" entry... a "short update" and a "lengthy rant on the stupidity of politics".
Of course, once this feature is active, I can think of a bazillon more things to do with the data once we have it. Just as a taste... a user could provide a link on the top of their journal to "poetry", show casing that users poetry. Or "photography", should a user be into that sort of thing, to allow visitors to see ALL of that users photography.
Then... eventually... with the new style system, perhaps provisions can be made to allow multiple lastn styles, so that my poetry page can look different than my short updates page. Or, provided this functionality is present in the new style system, allow me to show my most five recent "short updates" at the top of the page in a box, followed by the one last "lengthy entry". The possibilities are endless. And besides... having meta-data is just plain cool.
I know building these sorts of things takes time. However, if we decide to go forward with this plan, I strongly suggest adding the meta-data field before allowing users to filter by it... that way, while the feature is being coded, journal users can be categorizing their journal entries for use when the feature is finished.