Bard - has CC that targets all three saves and can buff your party.
At the end of the day its mostly Enchantment, which half the mobs in the game will be either outright immune to or highly resistant.
Plus some cool Fortitude 1-round Stuns/interrupts, that are a bit unwieldy due to the cone aoe. Reflex? Not sure what Reflex spells they got? Grease I suppose?
A Bard's CC has NOTHING on a mage's Conjuration goodness. Also a Bard can't nuke.
Alchemist - targets all three saves with his bombs and can buff the party.
Kinda cool, but the aoes are typically pretty small. Limited in uses. Sure, as are a mage's spells, but I feel that typically 1 arcane spell makes a much bigger difference then 1 bomb. Sure can spam-destroy bosses, but so can a mage with rays - or outright disable them with hard CC like Chains of Light.
They are good, but not my taste (like Vivis though).
Cleric/druid - targets all three saves with his spells, buffs and heals the party, brings pet and has access to unique domain stuff.
Good at what they do, but miss mass hard CC options. Also cannot really compare the nuking potential.
Magus/vivisectionist - strong damage dealer, brings buffs for the party.
Sure, they are good, but that's another role - melee DD.
Sacred huntsmaster/ranger - good damage, has buffs (well, ranger at least can buff himself) brings pet.
Again, a different role. Cannot CC effectively, cannot Nova.
Well yeah, that's an interesting one. Potent, certainly. But far less versatile. IMO brings much less to the table prior to level 13. Afterwards if going for Deadly Earth risks becoming a one-trick-pony with rotten gameplay that gets old real fast. Otherwise... still inferior.
So no, I'm not convinced anyone else can do what an AT does but better. Other roles - tanking, melee DD, sustained DPS, healing, buffing, sure. But IMO noone can beat an AT at nuking or mass hard CC (okay, some sage sorc or something might have +1 or +2 DC more... big deal). Plus all the ranged rogue utility. Well, the Cross-blooded Sorc from EA mod can probably come close in nuking, while being easier to use.