Anyone who is testing Highmaul on beta right now is more than likely using T17, which we won't have on live. So results will be quite different with all classes having 0 set bonuses. Highmaul may not have too many cleave/aoe fights but Blackrock Foundry will.
Retribution spec with tier 2/4 set bonusses is realy over the top in a funny kind of way. It makes the spec so orgasmic in therms of the brain processing the procs and procs from procs that you are realy never bored lol. I understand that some people might find it ridiculous and goofy, and other people might find it a nuisance and way too confusing, but it's a heck of a fun spec in my personal humble opinion.
Unfortunately i think that people who can't get the tier set will miss out a lot on this new gameplay and probably the set bonuses should be in the talent tree for player chosing that kind of "random" gameplay, instead of a tier set.
Tested Normal Mode Highmaul last night, and ret is looking pretty strong. Definitely in the top 5 if played correctly. Good Single target, good aoe, good cleave. Had a hard time figuring out a glaring weakness with the addition of 2/4s. Don't have any logs, but here are some vods.