I honestly still think Lati@s' better offenses/bulk and speed would usurp any role that empoleon would possess with reliable recovery as a specially defensive baton passer. The two main advantages it has are its typing scald, but Latios' surf hits just as hard, albeit forfeiting the burn chance. While empoleon's lesser stealth rock weakness also seems a bonus, it's forfeited by the fact that it's affected by both spikes and sticky web that it might want to clear. While empoleon has decent resistances (even with the steel nerf), they're mostly to attacks commonly paired with other things that hit it supereffectively; rock is often seen alongside a ground type attack, as is dragon. Ice is usually used alongside an electric type attack, and bug (since U-Turn is basically the only half decent bug move in OU) is almost always paired with a volt switch user (and other stray bug attacks, like heracross's megahorn, are also usually accompanies by a supereffective hit). The biggest niche that empoleon brings is its ability to switch into water types with ice type coverage, whereas Lati@s (mostly Latias here; Latios is kind of differently played, since he's not usually running a specially defensive set) is much better able to wall the threats of OU, especially with drastically increased bulk. Even if the penguin got, say, roost, it would still be, in my opinion, inferior to Latias in at least 90% of cases.
EDIT: Hm... didn't realize it gets knock off. Which gives it some niche, although I maintain that Latias would still outclass it most of the time due to her superior bulk. I still think support mega-scizor is 100% superior as a defog + knock off absuer (and imo possibly the most underrated pokemon in the current meta), but if you're not up for using your mega slot for him, eh.
