That doesn't exist in D&D. If your damage is slacking, the DM should make up for it and not throw monsters that have a truckload of HP at you, or fudge rolls, or make it do stupid/non-optimized things to compensate and even the playing field. D&D monsters don't have to follow a scripted AI and after X minutes it does 10x the damage and wipes (TPKs) everyone.
True. At the same time, a DM probably doesn't want the PCs to basically figure "why bother, no matter how bad our tactics, our character building, etc ... the DM will just make the fight easier for us". They should at least be trying, and the DM is trying to challenge the party.
That's one thing the CharOp guys have never gotten through their head; not in 3.5 and not in 4e. Yes, everyone wants to be the guy who pulls out the uber-attack and pulls out insane damage in a single round, but it's not a big deal when the DM can adjust things on the fly to react to situations and throw you a bone if nobody is optimized for a lot of damage. IMO as long as a Striker can dish out a respectable amount of damage, they're good enough.
But, the question becomes what is respectable.
And, for optimization, which is what Char Op's goal is, making a striker do his job as optimally as possible is something to try.
Some of the characters aren't meant to be played ... they are meant to show the designers that, for example, rangers have ridiculously high damage output because: (a) multiple [W] x2 is much better than 2[W] even if you get rid of the ability modifier and (b) Even if you only quarry damage 1/rnd, attacks via immediate action dramatically increase your damage output.
There are some people that refuse to play with someone that doesn't Char Op, but that's different from the intelectual exercise that is Char Op (And, some people benefit from it because, frankly, there are tons of options out there and it's nice to have someone already doing the work of figuring out what stuff is helpful and what isn't, etc).
I
do agree that focusing on DPR exclusively is problematic. For a striker, you DO need other things ... you have to get where you need to be (if you are melee) or you have to get at who you want to (in terms of ranged attackers). DPR is a combination of damage and accuracy of course. And you have to worry about keeping yourself alive as well. If a striker does tons of damage but requires a dedicated leader to keep the glass canon firing and a defender to keep him alive long enough for the leader to heal him ... he's not doing a good job.
Nobody is running Recount (for those who don't know, Recount is a WoW addon that tracks your DPS, and is basically an e-peen meter used to ridicule people who do under a certain amount at a certain level with a certain spec and certain gear) and calling you a baddie and a scrub and kicking you out of the group for doing under 40DPR or whatever the "ideal" range is at a given time, because the output doesn't matter nearly as much.
It doesn't matter as much, but in a "normal" fight (i.e. one that the DM doesn't just change half way through) DPR translates into how quickly a monster dies. A few choices to optimize DPR and, with good tactics, suddenly a monster dies a bit quicker, so it's dealing out less damage (making the leader's job easier), it isn't trying to get to he squishies (making the defender's job easier) and it doesn't need to be locked down (making the controller's job easier).
Basically, the striker's job is to kill things. Calculating DPR is a mathmatical way to estimate how good the striker is at killing things. So, if someone is playing a striker and asking how they can do their job better ... one answer is to increase their DPR. CharOp can tell them what feat, for example, will increase their DPR the most.
Regardless ... back to the actual thread:
A - Strikers will almost always end up looking at superior stuff because they want to increase their accuracy an damage, and it's one of the better options to do so.
B - For defenders, especially defenders that attack as their mark punishment, accuracy and damage are also important. For say a paladin who uses divine challenge/sanction which auto damges, it's not as important from a defender perspective. Depending on power selection and secondary role, they may also want the damage boost.
C - For leaders, some leader powers (most pre-essential non-dailies) require you hit, so you want to increase accuracy if you can ... and unlike a defender, you don't benefit as much from being adjacent to enemies, so reach weapons are also nice. Damage boosting isn't as important, it's quite down the list of priorities. So, for the most part, the reason to grab a superior weapon is for reach, accuracy or both.
D - For controllers, you only really have the seeker and hunter (and special case with Arcane weapon prof + polearm blades + polearm momentum ... but that's one of those CharOp things I would guess many DMs would shut down) that would take superior weapons. Both are ranged. For the hunter, they can get the extra accuracy by grabbing a superior crossbow and not have to worry about the reload restriction. They can also go with the greatbow to up their damage if they want to be secondary striker as well (which with tricks like multiclassing into seeker to get the paragon damage boost to all RBAs ... which are nearly all attacks for the hunter, can get pretty damaging). The seeker is an odd case. Jumping to a greatbow may not be worth it, but for a thrown weapon, it may be (Although their "best" bet for the thrown build is getting a magic property added to a weapon that let's be it be thrown, but considering they only get simple melee weapons, they don't have a ton of good weapons to begin with, the morningstar gives them the same 'stats' as a longbow, but they have to make it magic and even then it has shorter distance...).
So, basically, that's the order of importance. The seeker, especially throwing weapon seeker, is sort of in a box of his own, which is that it realy wants to take weapon proficiency but the weapon it wants doesn't actually exist ... the best they can get is a weapon slightly better than a dagger or slightly better than a javelin, so unless it can get a magic property tacked on that let's him throw it, he doesn't get much benefit for going from simple to superior.
In the example of the archer warlord: Taking a greatbow (or a superior crossbow along with the fast reload feat) are probably not worth it. Feats to improve your ability to lead are better than improving your damage. Generally speaking, being better at your role is probably better than being better at a different roll. If you have nothing else to do ... falling back on increasing DPR (accuracy and/or damage) is always a safe bet. But, if you have better options, such as making you a better leader, you should probably take those first.