PVP gearing:
Cataclysm will allow for more varied ways of gearing up for PVP. The term "Rated Battelegrounds" keep showing up in blizzards statements, and probably indicates that an alternative route for gearing up will be established in parallel to the arena gearing system, or that they may be somehow integrated, like, for example, the current ability to get arena points threw completing BG dailies.
The emphasize is to make BG gearing feel less "grindy" and more skill/ wins dependant.
In addition the first few pieces of PVP gear will be more easily obtained, so that players won't have to rely on PVE gear in order to win the first season. It is safe to assume that you will be able to obtain resilience pieces of armor easier, at least for your first couple of hundreds point of resil. This will also reduce the "Too Bursty" feeling of the first season.
PVP viability for every spec:
The future specs design will try to make every classes spec viable in at least one arena composition. That said, blizzard didn't specifically mention tanking specs for example, though some players find them viable already. My assumption is that they were referring more to some "hybrid" classes specs that currently lack PVP viability.
The shift in PVP design will be less on "solo" PVP concerns, such as "this spec lacks CC" and more of a "team" concern, such as "This spec doesn't feel like it's contributing enough to be considered for a certain setup"
we think one of the problems is that we've spent too much effort balancing around specific specs instead of teams. But it's actually the comp that is super important. In the past we've given a spec with presumably low survivability more survivability or a class with marginal CC better CC. Increasingly though, we think that's a shotgun approach. What we are doing now is looking in terms of a, typically 3-player, team. What does a Balance druid bring to the table? Why would you want a warlock instead of a Frost mage? Those types of questions. We want to make sure there is at least one viable comp for each spec and then we can adjust those specs by answering the question: Okay, why is A being brought more than B?
The flip side of that is why you'd want to be spec A of your class when spec B is more attractive to the other players. Whenver you buff A, you risk B falling off though.
Too often the forum discussions (and not just our forums) rally around very specific questions, such as: how do I beat this guy? Or, why do I get blown up so fast? Those can be useful at identifying weaknesses, but ultimately it's the synergy with the other players on the team that is more important. (I'm only talking about Arenas here. Coordination in BGs is still important. It's just very different.)