I'm kind of waiting to see what "glaring holes" a party line up might have to figure out something needed. We're told in the kickoff post that scout and healer are going to be needed, and if it's a really big party (up to 9!) it makes me think multiple healers, as how's one guy going to fill up the healing needs of say, three brick sh*thouses (assuming high CON dwarves)?
So yeah I think so far above I'm seeing a Face/Buff, maybe three Tanks (one or more of which might scout) but no Healers yet... no Nukes... no Archers... don't know.
For what it's worth if there's people thinking about "gee what are roles commonly known in gaming circles", I think a cut and paste of some of Zelknolf's AI stuff may remind of how many roles can be imagined at least for NPC hostiles. PCs don't necessarily fit into those categories (like it misses out on the social aspects) but it can sometimes be interesting to see one's own PC creations through this lens.
Tanks-- will prefer melee combat and fight defensively. If there are many of them, they will spread out and attempt to limit mobility through the battlefield. They are less concerned with killing their opponents and more concerned with holding them up.
Flanks-- will prefer melee combat against soft or distracted targets. They'll look for someone else to bother if they get attacked, and will try to use the clutter hopefully created by friendly tanks to shed the attention they've gained.
Shocks-- will charge recklessly into the fray and hack at anything that looks like it will die in a few hits; they're especially fond of chopping up spellcasters, if they can figure out who they are (which more or less requires that one of their party members see the spellcaster casting a spell). If they can identify a healer (e.g. one of the party members identifies a healing spell cast with spellcraft), they prioritize on killing healers.
Buffs-- will put preference on improving the fighting abilities of their friends with boosting and protective magic. They will not engage in fighting themselves until everyone in their party has all of the buffs they can provide, or they run out of buffs-- and if they have no buffs, they act like medics before turning to weapons. Once they do take to combat, they prefer ranged combat, and will try to shoot whoever they can get without chasing.
Medics-- will put preference on healing their friends before anything else. If everyone is healthy, or they're out of healing spells, they will default to buffs and summons. As a last resort, they'll use ranged combat to try to pick off weakened enemies. Of special note that it's assumed that all friendly units know who the medics are, and they will run to the nearest one when badly hurt-- don't set this flag on an NPC who can't actually help those dudes. Unless you're some kind of sadist.
Skirmishers-- will use ranged combat when it is an option, preferring to strike at soft targets, but will switch to melee if engaged in the melee. They will use selfish powers if they have them, but usually when they can't be shooting people for whatever reason.
Archers-- will prefer ranged combat; if engaged in the melee, they will flee to someone as a 'rally point,' and only switch to melee weapons themselves if that doesn't let them get away. Flanks will respond to this sort of fleeing, as well, and people chasing archers (or medics, for that matter) can expect to take sneak attacks.
Controls-- will attempt to achieve the same goals as tanks, but with magic-- they will use large, battlefield-altering area effect magics, if they can find a way to cast them without exploding their friends, and will summon allies as frequently as they can. Once out of spells to do as much, or if they can't safely target those spells, they will turn to targeted aggressive magics, dispelling, and buffs-- when totally tapped out, they turn to ranged combat, like a medic.
Nukes-- will put the highest priority on targeted aggressive magic, preferring ranged single-target and party-friendly area spells (e.g. missile storm; firebrand), and will target the strongest opponent that they're aware of (note: they don't metagame; they're going to guess based on gear, actions, and relative number of sparkly magic effects). If they run out of single-target spells or can't find a suitable juggernaut to pick on, they start behaving like controls.