If there was a question about how Blizzard planned to deal with Arena points in Wrath of the Lich King -- which seems so palpably close -- Wryxian explained their resolution to the problem of carrying over points from Level 70 to 80. The answer? They won't. Players who hit Level 71 will have all their Arena points reset to 0 and be removed from all Level 70 bracket Arena teams.
New skirmish brackets will open up for those between Levels 71-75 and Levels 79-80. As mentioned before, Level 80 players will be able to participate in rated matches and be eligible for Level 80 Arena rewards that will, thankfully, look distinctively different from PvE gear. This means that players should be spending their Arena points now instead of banking the maximum 5000 points, as it will not carry over past Level 70. In this scheme of progression, Level 70 Arenas will conceivably die an eventual natural death.
What does this mean for the current season? When the pre-Wrath content patch is released, we're likely to see a shake-up in class representation in Arena play, as more classes become viable. It is also highly likely that the current season will end when Wrath is finally released, and competitive or rated Arena play will be in a state of limbo as Blizzard is likely to allow several weeks for players to reach Level 80 before starting a new Arena season.