Once you enter the ready room to start a mission, your equipment is more-or-less fixed.  You’ve made your selections for what is available for the mission.  When you click ready, the system – at that moment – generates the encounters.  It scales the encounters based on a target skill level, but the content is not generated right up until you click ready.  That’s essential for game balance – and once you’ve committed to the mission, either the mission is a success or the mission is a failure.  From a storyline standpoint, a success can be a draw – but the mission itself has to be succeed or fail (either you achieve your objectives, or you don’t).

In D&D, you have a concept of a challenge level.  If you start with the players’ combined level, and you multiply it by a target challenge level, you get an encounter’s combined level to be a challenge.  Then you split those points between the targets.  You set the challenge level, and then from that, you determine what the mobs must be to compete.

For each of the three stat totals – ranged, support, melee – you split that in half into a defensive score (all available, with current skills and gear, defensive abilities) and an offensive score.  You multiply the defensive score by the challenge level, then rotate one position – and that’s the mobs offense.  The pool of points will be strong against what the player is weak against.

You do the same with the offensive score, but rotate the other way – and that’s the defense pool.

Then – from those numbers – you generate the encounters.  And so the mission ends up being the target challenge level, regardless of who attends it.

Gandalf didn’t make Gimli go taunt the Balrog.

Strider didn’t stand around looking for a tank.

Lina Inverse doesn’t have Gowry do all the tanking.

The running headlong into a group thing – and having the group try to take you down – is fine.  But it can’t be “let me hold all your attention while that archer over there skewers your friends one at a time” or “let me hold your attention while the guy in the flimsy silk dress hits you all at once with a huge honking ball of fire.”  Ideally, all three core skill sets would be capable of both taking and dishing out damage, so that the fights are more like the main event in a movie, and less of a seeing if you can hit 100 on the threat meter.

And defense doesn’t mean “stand and take damage without doing anything.”

Most – if not all – defense should require active participation.  That’s why we need the rock/scissors/paper – if you just stand there, one of the other offense types will always hurt you unless you’re actively dodging and countering.  That’s the point in a game – to play it, to be doing something – not to be standing there calling the mob names while some dude tripped up on acid yells “heal” over and over again, then you all sit around taking bong hits afterwards from some pusher before you head to the next mob to repeat the same pattern.

If that makes sense?