MattV commented in response to my post last week about setting numbers to describe monster difficulty. His experience in the old days didn't have much to do with trying to arrange fights that were at a particular challenge level and were more about 'let's go into this premade dungeon and see if we live' kind of play. I wanted to talk a bit about that and why I see the necessity for building a robust system to describe monster difficulty.
Back in the old days of DnD monsters didn't have to challenge the party because they challenged individuals. Even if you had a ten person party and you were facing down two orcs those orcs could roll well on initiative and swing their axes for enough damage to kill anyone in the group. Even though the party was guaranteed to win the element of danger was always there for any individual member so the GM never needed to calibrate the encounters tightly to keep people on their toes. Even if the monster didn't kill you the group only had a handful of healing spells for the day so a single hit was a significant drain on resources. The trouble with that model is that characters become disposable and investing in one is almost silly. It is a game of attrition rather than an epic tale.
These days people expect that their characters will live. Certainly this is true in 4th edition DnD, DnD Next, and Heroes By Trade. There are a variety of mechanics in all three games that mean that it is *possible* for a character to die in a fight that the party wins but the default expectation is that everybody walks out alive or everybody dies. In that sort of scenario if the encounter the party faces is utterly trivial then nobody is afraid or worried. That same ten party person facing down two orcs lacks any sense of danger or concern. This is good from a character longevity standpoint but has the issue that in order to keep the players cautious and worried the fights have to actually threaten the whole group. Of course if you want to threaten the group but not kill the group you need some sort of system to figure out how to do that.
This is where Challenge Ratings, Encounter Strength, and XP value come in. All three are systems to tell GMs how tough a monster is. All three have issues. Challenge Ratings from 3rd ed. suck because optimization makes such a difference in that system. An encounter that is barely winnable by a normal party is completely trivial for an optimized party and this makes the system not very useful. XP values from DnD Next have the problem that the scaling is completely off - they work for fights with a handful of enemies on each side but if you fill a tenth level fight with the appropriate number of orcs the players get massacred. Encounter Strength is the most robust system of the three but it isn't perfect either. At the extreme ends of the fight spectrum where the players face a single monster or a swarm of dorks the system isn't as good as I would like, though it is still the best of the three.
There is another motivation for creating tough but winnable encounters that I have not touched on so far though and that is that they allow for a challenging tactical game. Many players like combats to be a challenge and they want the combats to be tough enough that they have to play well to win. Without a good system it is extremely difficult to provide fights that force the players to think hard and play well but don't accidentally kill them off on a regular basis. Personally I love the feeling of being in a tough fight and having to optimize my actions so I really appreciate when the GM gets it just right and we need to play superbly to pull out a victory.
Of course not everyone really wants the party to be challenged nor do they want a tactical game. For those folks these systems aren't very relevant as they aren't trying to walk the razor's edge. All they want is something rough to tell them if a monster is way out of line for the group. Nothing wrong with this of course and as long as they are enjoying it then more power to them. For me though a well built challenge system is key on either side of the GM screen and while building HBT I definitely want to provide such a system for those who want to use it. Moreover my perfectionist tendencies make me want to keep on tweaking and perfecting the system far beyond what most people would consider reasonable or necessary. It feels in many ways like what I was born to do (if such a thing truly existed).