Working with Sticky posts currently is very awkward for a theme developer, you can't easily 'float' stickies within a category to the top of the category list, show stickies at the top of search results or really do anything interesting with them without coding multiple loops into a page and splicing them back together - it gives me a headache even thinking about solving the resulting pagination issues.
This is all because they are stored as a serialised string in the options table. If they were just another class of meta data in the meta table you could easily query against them to set result orders wherever you wanted to use them.
Furthermore with this framework stickiness could easily be implemented as a scale, eg a stickiness value from 0 - 10. Theme developers could then use it for all kinds of custom sorts, ratings schemes could easily be hooked to stickiness etc etc
Imagine how useful it would be to do something like: