So far it looks like the Mac Mini and Mac Pro will not get an update. MacBook Pro, MacBook Air, and iMac at least have rumors of an update. Maybe someday, the only Mac Apple will sell will be the MacBook Pro.
Seems like the entire laptop line up will be updated, if we're lucky even the new Macbook. The iMac will probably get new graphics. As to the other desktops, I don't know. The Mac Pro might get at least an announcement of something to come, cause it's been three years already! As to the mac mini, I don't see them still selling Haswell machines. I guess it will be either updated or EOL'ed.