That would be quite a change -- since the beginning of the game, Hunters have relied on mana as their "resource" -- Warriors have Rage and Rogues have Energy, but Hunters somehow got looped in with the other DPSers as mana users. That doesn't make much sense -- not only does it depend on Intelligence (a stat which Hunters don't really have a reason to go after anyway), but it's lead to the problem of keeping Hunters powered up. Hunters are almost continually out of mana, and Blizzard has made some wacky mechanic tweaks (with both AotV and Replenishment) to try and keep them up and running.
So maybe a non-mana system is the way to go with Hunters. But what would it look like? A Rune-style system, where spells are based on cooldowns of limited resources? Brigwyn recommended "Ammo" as the new resource system on the podcast, and maybe that's the way to go: unlimited ammo, but with a certain number of "shots" per second, that regenerate like a Rogue's energy, where the strategy lies in choosing which shots to take when. It seems late in the game's life to make such a big change to the way the very popular class works, but we can't wait to hear what Blizzard's thinking in a few weeks at BlizzCon.