Part of Scott Hartsman's Rift State of the Game is a plan to introduce alternate advancement at the game's level cap. While I am a non-raider who does enjoy continued progression - the theoretical target audience for this system - I am not convinced that this is a good idea.
I'm curious what Scott thinks of the AA system over in his old game, EQ2, where players arrive at level 90 with less than half of the current AA cap and can expect a lengthy grind to obtain class-defining abilities in their AA trees. Unlike gear, there is no short-cut involving plat or guildmates willing to hand you loot - your AA will remain substandard until you've played "enough" to fix the problem. This is fine if you're happy with what you're doing while you play and less fine if having a minimum number of AA is a balance requirement for your friends to be allowed to bring you on raids.
Meanwhile, the balance implications are significant. In the short term, this is yet another form of vertical progression that will make the repeatable content that is intended to keep players in the game easier and easier with each passing day. In the long term, it's not just group players who face content balanced around the assumption that players have AA - either all future content will assume some baseline level of AA or all future content will be easier than intended for current players. The former is a problem for new players (who would have to stop and grind AA before continuing to grind levels so they can get to the cap and grind more AA). The latter is a problem for current players (who will find each new expansion's difficulty ruined by their efforts in the previous one).
I understand the appeal of the alternate advancement - it's a way to give players permanent progression in chunks that are much smaller than additional levels (which would have an especially big effect on an open ended class system like Rift's). It is possible that the system could even be used for something unique and interesting, though it's equally possible that it will be reduced to boring but mandatory stat bonuses. In either case it is unlikely that the game will break on the day the system comes out. In the long run, though, Trion might end up regretting the decision to add more vertical progression solely for the sake of progression.