[Tuoweit]

a cap doesn't actually accomplish the stated goals.  Communication does.

Of course; just stating a cap with no context is pretty meaningless and doesn't convey intent.  I suppose my play experience must be exceptional, as I consider things like such communication as a given, usually.

[RHat]

Ah, but if the GM is communicating "For this game, this is the sort of power level we're dealing with", what need is there for caps in the first place?

[Tuoweit]

Ah, but if the GM is communicating "For this game, this is the sort of power level we're dealing with", what need is there for caps in the first place?

How do you define "this sort of power level" ?  One way, is to use dice pool caps.  They are unambiguous and not subject to varying interpretations of what "low power" or other relative terms mean.

[RHat]

You use benchmarks.  Very different in principle.  You define, roughly, what a given level of ability looks like in terms of dice pools, explain what sort of game you're looking for, and go from there.

[Michael Chandra]

I currently have the enemies of Dragon's Song as my benchmark for tough SR5 campaigns. It's an easy way to figure out what the tough level is again, since I immediately have their numbers in my head (also known as "my shortly-after-chargen character stats".)

[baronspam]

stuff

(Please let's not digress into "what is min-maxing", I'm just noting that there's a difference in definitions and leaving it at that.)

If you are going to tell players "don't min/max your characters" you have to be able to clearly define what min/maxing is.  For one person, that is an 18 dice pool.  For me min/maxing is a build that, while legal, so neglects certain aspects of the character as to create a character with such glaring deficiencies in the min areas that it is hard to accept that such a character would succeed in getting to the start of play.  You can build the 25 dice sniper that I outlined above, but after you find priorities for elf, priorities for magic, the resources for the enhancements, the attributes needed, etc, you either end up with terrible skills in other areas or blatant dump stats to get the high agility.

Remember, characters are supposed to be (in a standard game) highly skilled professionals.  They are going to be better, in many cases much better, than the typical security guard, patrol cop, or ganger.    Such opposition is not the real threat, and a corporation with huge resources is not going to protect something really valuable with six rent-a-cops armed with light pistols.   

[Tuoweit]

If you are going to tell players "don't min/max your characters" you have to be able to clearly define what min/maxing is. 

I agree completely.  But what you or I or anyone else on this forum besides the OP thinks is min/maxing is entirely irrelevant to that conversation and discussion between the OP and his players, which is why having that discussion here is pointless.

[Tuoweit]

You use benchmarks.  Very different in principle.  You define, roughly, what a given level of ability looks like in terms of dice pools, explain what sort of game you're looking for, and go from there.

Is this not just the same thing with a different name?  You could say "well they're just guidelines, not a hard cap", but then at some point you have to draw the line beyond which someone is drifting too far from the guideline.   Then your guideline simply becomes a cap in disguise, a signpost if you will, a couple dice shy of the actual cap.  Why beat around the bush?

Whatever you call them or however you dress them up, though, if a player doesn't (or won't) grasp the concept behind those rules they may still come up with a bizarre character that follow the letter of whatever rules you present yet manages to defeat their purpose somehow (like the "every dice pool at 14" character that someone mentioned).  I'm not sure how to deal with that; I've never had to.  I suppose one has to consider the possibility that said player's playstyle is simply not compatible one's own.

[MadBear]

Min/maxing has it's benefits, and it's drawbacks. Sure, I can easily create character with a starting dice pool well over 20. but so what? By doing so, I have to put resources into that, Attributes, Skill Points, Advantages, Cyberware or Power Points, Gear, etc. That means fewer resources for other dice pools. It's a matter of choice, you can choose to play a focused character, or a well rounded one. You are taking away your player's choice, to suit your own preferences. There are plenty of ways to deal with 'overpowered' characters, you don't need to impose strict creation rules.
Even then, Min/Maxing is all relative. I have an Orc sammie with a Pistols Dice Pool of 20, and Unarmed Combat of 18; I don't consider that Min/Maxing at all, as he only has a base AGL of 5, and Muscle Toner 2. By definition, in order to 'Max' I'd have to have an AGL of 6 and Musc Ton 3, right? And regarding Unarmed DV, he only has a STR 5, low for an Orc, with some Muscle Aug 2, and Aluminum Bone Lacing. Again, to MAX his unarmed DV, I would have put his STR at racial max, MT 3, and Titanium Bone Lacing. On the other hand, he's not good for much else, other than taking a bullet.
As for having a Dice Pool of 18 on a Street Level campaign, I don't have a problem with that either, even as a GM. Refer to my first paragraph about resources. In a Street Level game, resources are going to be even more limited, so the disparity between that Dice Pool and the rest will be even more marked.

[Michael Chandra]

If you are going to tell players "don't min/max your characters" you have to be able to clearly define what min/maxing is. 

I agree completely.  But what you or I or anyone else on this forum besides the OP thinks is min/maxing is entirely irrelevant to that conversation and discussion between the OP and his players, which is why having that discussion here is pointless.

Just a minor tip: Don't ever start up something you're not interested/willing to finish.

And no, benchmarks and caps aren't the same thing in disguise. There's a big difference between going "just keep X in mind" and "no, you are not allowed to go beyond point X until I say so". The first is a guide, the second is a law you make them follow, and as a result make REALLY aware of. That basically translates to that they feel pressured to be able to hit that and be ready to go past it the second you allow. There's a big difference between noting your expectations and engaging in an arms race.

[RHat]

If you are going to tell players "don't min/max your characters" you have to be able to clearly define what min/maxing is.  For one person, that is an 18 dice pool.

I'd point out, again, that you can't define min-maxing without defining the "min" component; dice pool size only references the "max" component.

In any case, benchmarks are different than caps in a number of ways.  In addition to what Michael Chandra pointed out, benchmarks aren't simply a high water mark; the idea is to assign meaning to a given dice pool size.  This actually tackles the power disparity problem from both sides of the coin, for that matter.  And there's no hard value where you cut things off, but you do make sure that the concept and dice pools line up and that the concept belongs in the game.

Also, it's worth noting that it's "benchmarks" plural, not singular.  You have, say, 5 values with a descriptor for what they mean in your game to create a scale.