What makes you think those are client problems and not back-end problems.. Especially things like "changes to your profile take hours to reflect or reflect inconsistently" sounds like back end to me..
A fair point but (a) my observations are still accurate (just scratch 'client') and (b) going off-topic, it makes me question the management structure at Facebook (re: recent post on HN) where they end up building a complicated set of features but can't build the back-end to support it.