You really do have rage problems don't you?
In regards to feud, you're only right about lichborne being useful if your healers are bad. Otherwise two or three DS will be more than enough to help you get to the top while only marginally lowering your DPS and interrupting your rotation. Lichborne will stop your dps rotation and dump your RP's to heal you up. It's a matter of preference and if your healers are actually worth their weight.
Could you name a fight that has adds that doesn't require some sort of interrupt?
Maloriak: adds must be dps'd down, chilblains is very helpful in this fight, you can gain some RP here, but you may also need to interrupt Maloriak a few times.
Omnitron: adds, but one of the bosses must be interrupted the whole time he is up, my guess is EW is a net gain for this fight unless you deal the killing blow to more than one add and are not chased by any adds
Nef: Both Chilblains and EW are nice, Chilblans in p1 (and p3 in emergencies), EW reigns in p2, allowing you to maintain your DPS rotation and interrupt
Magmaw: EW is not very useful, but 1 point for normal, possibly 2 for heroic in chilblains (and let's be honest, if you're a frost dk on this fight, chances are you'll be the add tank)
Cho'Gall: Adds throughout the fight, interrupts in the final phase
Princes: Chilblains helpful for adds, EW not so much
Halfus: depending on your pull for the fight, EW and chilblains are extremely useful
Ascendent Council: possibility to be an interrupter in p1, chilblains not so useful
So 7/12 these abilities are useful, some fights more than others, as with any utility ability. This ignores many trash pulls which require interrupts in the raids as well.
I dunno about you, but my guild doesn't want me to respec every fight (especially if I have a tank OS for some fights), so if we're talking about a marginal gain from going butchery in 3 fights, it's not worth it to me unless I'm just trying to pad the meters for an extra 50-75dps (if that).