I believe a system starts falling when you actually try to "Balance" classes. I honest to god LOVED SWG before the player base kept crying BALANCE OP NERF therein. You are never going to have a regular assault infantry beat a tank in modern day combat. However if you have a specialized team of Demolitions or Heavy Weapons the opposite is relatively true of course given that margin of error (lucky shots and the sort) however I only ever see the tank with a lucky shot. That is what I liked about SWG at first. You had certain classes that could not stand against another class even if they had a fully upgraded toon with all your skills and best crafted wep.

I believe if FO wants to stand apart they need to embrace this idea and let gamers get used to the fact that sometimes they just will not be able to win, this will give you the option of still being solo but help encourage a grouping environment. Being an MMO I believe the idea that you can do things alone is a bit over done (for lack of words) MMO in itself stands for a community and working/playing with others. Until WoW came out it was rare to see anyone soloing 90% of their game career, IE> EQ,DAOC. I am sure post apocalyptic towns you need the same cooperation to be built and have a somewhat governed and comfortable life. Do not get me wrong though I do not mean forcing groups to get anywhere (Final fantasy) but encourage. Just some thoughts, and feedback would be nice to see what others may think.

Here's two examples of what I believe is PvP balance.

Ex 1:
*Power armor dude with minigun sees sneaky guy with infiltration armor while not sneaking. Rains down a box of ammo and the sneaky guy lies all over the place in shreds.
*Sneaky guy sneaks up to power armor dude and attacks him from behind with his ripper. He scores a critical hit because he partially ignored the armor by slicing in the plate joints and punctured power armor dude's spine. He finishes him up before he's able to react.
*Sneaky guy is less experienced than power armor dude and doesn't know that he has reinforced his vulnerable joints. He fails to penetrate his armor and now power armor dude pummels poor sneaky guy to faceless pulp.

Ex 2:
*Sneaky dude trails explorer pal while he's busy checking out some sea-weed that could be used for fuel. He's got no problem slicing explorer pal's throat and takes his precious loot.
*Explorer pal strolls around the desert and notices sneaky dude trailing him because his explorer-sense is active. He lures sneaky dude in a bear-trap and cuts his leg in two. He finishes him off with his viper-venom coated 9mm bullets.

The visual I just got of a guy holding a snake in one hand, and shoving a bullet into its mouth with the other, while yelling "NOW BITE, DAMNIT!" was awesome.

Paper-scissors-rock balance schemes in PvP that are too extreme though aren't good, because they heavily discourage engagement. If paper attacks rock, rock should always consider fighting back, not just run away. If scissors are in a bad position, paper shouldn't be afraid to attack and attempt to exploit it. Maybe you'll sit and sigh, wishing that I were near
Then maybe you'll ask me to come back again
And maybe I'll say "Maybe"

I ask this then, why would anyone choose to roll a character that was in fact "made" to be dominated? And let's say that these characters have certain skill sets that are desirable, but they must rely on a group to survive combat, then in fact they must rely on individuals to keep them alive, individuals that may or may not be team players.
Of course you could circumvent the random groups by joining a guild right off jump street, but I myself don't really want to join a guild till end lvls when I start to concentrate more on pvp action (and most good pvp guild's have a lot of mandatories and clan meeting etc, which can interfere with questing).
At some point it should come down to a players skill and not whether he rolled a op class, or a squishy little bug class.
I don't believe that all characters should be 100% even, nor do i believe there should be no group options, and some content should be completely team based, but some modicum of balance can really go a long way IMO.

I think you've just found the Vault Boy image for Poisoning skill

By in no means do I mean to outcast any one class. Given the right situation any class should be able to stand against another class.

The focus was and here is an example.

You have 8 classes.
You would be able to trump 1 class with relative ease ( your his anti class)
You would be trumped by 1 class (he is your anti class
The other 6 would be basically a fairly level playing field maybe given a 10% margin in either direction.

It draws on, for lack of a better example and a common ground, take Vanilla wow.
A hunter could take a rogue given most situations unless he was ganked. This gives you the exploit said weakness but also has the definitive who should win normally.

So in this case I guess take one class acting as a hunter. He sees a I dunno Generic Melee guy (for lack of class idea). Hunter would normally be able to kite said melee guy in a normal given situation however if melee guy had the jump on Hunter crippling would ensue and beat down would be imminent.

So closer to what Hellis has explained.

I do not believe that 1 class against another class as such would discourage pvp your looking at a sub 15% encounter chance statistically speaking. I however do believe when you try to make everyone to close to each other with similar utilities that you lose the unique feel and have a bigger margin of having that one OP class.