How important is it to have one of each Archetype at the table?

Not at all.

it is however, more important to fill much more generic roles for balance, like at table of all archers or all ranged arcane casters probably wouldn't fair too well, similarly a table with characters that cant mass kill off minions wouldn't do too well either

I will disagree somewhat in saying that party balance, while not essential, is very helpful.

Having a Shaman or a Divine caster who can Diminish Fatigue is very useful, but can be done less effectively by those who cannot cast Corpus spells. Having a Martial character built for combat can help immensely in combat, but those who are less capable are still able to do it themselves.

Cody I don't disagree with what your saying so i suspect we are saying something similar from two different perspectives

Archetype is a very fluid concept. As discussed above, its more about the role.

I've seen effective Martial casters and Divine strikers. Expert could wind up anywhere (but misses out on access to a few Archetype specific talents).

Most of the important roles I've seen in the game. IMO a "balanced party" can fill all the following

COMBAT:

Tank/Defender. Absorbs a lot of attacks through high defenses, high AR or both (usually martial archetype or Ss'ressen) Traditionally also has some battlefield control through attacks that push clocks or stun enemies OR talents like combat challenge.

Caster. Usually has some control style spells as well as ranged damage. Often some kind of AoE to kill many minions at once. (Usually Arcane, Divine or Expert Archetype).

Smiter. Can do a lot of damage a couple of times with big hits. Usually through Smite Infidel and Murderous Precision (usually through Martial or Expert Archetypes). May also reflect optimizing clock to maximize number of attacks such as through spinning strikes.

ARCHER: can damage somebody at range. Often this roll can be filled with a caster or other characters who have secondary ranged attacks. (Any Archetype has the potential to fill this role.)

Healer\Buffer: is much less necessary in the A:RPG since people heal to full under normal circumstances at the end of every scene. (Often the Divine Archetype or someone with the Leadership talent)

NON COMBAT

FACE: the party's persuader. Has a lot of ranks in Etiquette and Persuasion. Maybe also Empathy and Deceit. (often Dive or Expert Archetype).

INVESTIGATOR: the guy or gal who finds clues. Has lots of ranks in Perception. Maybe also Empathy, Heal (for autopsies), Streetwise or Tracking. (Anyone really,probably most often the Expert Archetype)

Wilderness Guides and Scouts are sometimes desirable too but mostly just use a single skill.

The one thing I have noticed with the home group here is that the lack of a area effect spell to take down all the 1 hit minions really makes a huge impact.

Dean / Taffy
Melbourne Australia

In our home games, having someone who can cast Diminish Fatigue is a "must". When we're missing that element among the PCs, combats get a lot tougher.

Sure you heal up at the end of a Scene. But you need to survive the scene first. Without Diminish Fatigue, it's too easy for a front-line fighter to go down, leaving the second-line fighters to finish it. But they go down even faster. Almost like dominoes

Other abilities can serve the same purpose, e.g., Empathic Healing, Healing Embrace, Leadership. But if I had to pick just one, it'd be Diminish Fatigue, hands down.

Its called "Combat Loss Grouping" (for the technical minded). A GM recognises it a lot more frequently as his minions ablate away, it comes to the point (often within a few ticks) where he can call the combat.

Players don't notice it as often, until they're staring down a TPK after their lynchpin combatant falls and isn't healed.

I'm so glad that someone else has said this as I've felt this way for ages: as a Gm you know when there is no point continuing the combat but you do so anyway so that the PCs feel satisfied.