Whether they should have been doing it depends on how you use Facebook, I think. I tend to log into it once a day or so, so a non-chronological view actually suits me great. It'll be a shame if it goes away.
Whether chronological makes sense is a product of the number of times you log in and the number of 'friends' you have (and the number of posts they make).
I have 140 friends. I log in a couple of times a day. I have filtered all their crap. I want chronological order.
If I had 1000 'friends' who posted all day, then I would want a way more filtered and special-sauced feed.
