Been doing some testing on UH 2h on the Cataclysm Server
Obliterate (untalented) hits for roughly twice that of SS so I think with 3 points in anihilation (facilitated by IIT and whatever replaces RE) will give an alternative attack when a FU combination is available but diseases do not need refreshing.
Did some quick parses:-
SS in UH Presence
World of Logs - Real Time Raid Analysis 3400dps
OB in Frost Presence
World of Logs - Real Time Raid Analysis 4222 dps
Not very scientific I know, but best I can manage, both have extra Blood strikes due to runic empowerment making death runes back into blood runes /facepalm so presumeably both will be higher when RE works as intended.
Quickly changed my tank spec into 2h frost dps and had a quick go at that (never ever played frost before)
World of Logs - Real Time Raid Analysis 6156 dps
Excuse the crumby disease uptimes on these, didnt think they were that bad, but on further testing, it would seem that IT and PS can hit but not apply the disease from time to time :-/