To some players (mainly my fellow shaman), this change has been viewed as a huge nerf. Bloodlust has long been one of the main assets a shaman brings to an arena team. Ever since Season 1, shaman have been able to cite Bloodlust / Heroism as one of the main reasons they were allowed to PvP at a competitive level.
However, Bloodlust has been both a blessing and a curse for shaman. In nearly every season of Wrath of the Lich King, one of the most frequently cited complaints by enhancement shaman in arena was that Bloodlust was the only reason they were on the team. Beast cleave and enh/arms/holy paladin were both comps that relied on the shaman to Bloodlust so that their arena partners could dish out the major damage. Elemental and restoration shaman fared better towards the tail end of the expansion, but there still was an overall feeling that the strongest contribution to the team a shaman could offer was its Heroism cooldown.
Cataclysm isn't Wrath of the Lich King, and some of the class issues that existed last expansion aren't as prevalent this expansion. For the first time ever, we're seeing enhancement emerge as a strong spec in its own right. Restoration is one of the two strongest PvP healers in the game, running counter to holy paladins for that title. Elemental is lagging behind the majority of specs in the game, unfortunately, but hopefully with the nerf to Bloodlust, we will see them buffed to compensate. Overall, being brought as specs because the specs themselves are strong will serve shaman better than being brought as Bloodlust bots.
Ancient Hysteria and Time Warp were also problematic spells, greatly increasing your chances of running into a 30% haste buff team. Frost mages have historically been a strong arena spec, and Time Warp just was another slather of icing on the seven-layer cake of playing one. Removing Ancient Hysteria as a required pet buff also opens up beast mastery hunters to other pet choices in arena.
The Cataclysm arena design is supposed to be different. Blizzard wants arena matches to be won through outplaying the other team, not because one team had Bloodlust and was able to tunnel unhealable damage until it turned into a 2v3 match. Ultimately, this should be what the players want as well: an arena system in which burst cooldowns play a positive role, but also in which the overriding goal of the match is to actually outplay your opponents, not to outburst them.
For more on Cataclysm arena design and predictions, check out C. Christian Moore's Blood Sport column.