RFisher said:
In my experience, the CR/EL system is just as broken as the old HD+special abilities system. You can still have a TPK with a suppossedly easy encounter & a cake-walk with a suppossedly tough one. & such anomilies seem to happen just as frequently.
While the second sentence is true on its face, I think that it's important to consider several points when discussing whether the CR/EL system is "broken".
1) Not all monsters at a given CR are created equal. This is obvious to anyone with a moderate amount of experience using the core books. I mean, come on, the Mohrg is a CR 8 monster, but anyone who is more scared of a Mohrg than a Mind Flayer, Grey Render, or Ogre Mage has an atypical character build. This is inevitable due to the granularity of the system and the fact that different parties will find different monsters challenging.
2) The formulas used to create ELs produce approximate results. IMHO, two medium fire elementals aren't nearly as scary as a single large fire elemental, but they're the same EL. Once again, this is inevitable, as CR/ELs are a tool, and certainly not an infallible one.
3) Circumstances can radically alter how hard an encounter is. Either the PCs or the monsters may be stronger or weaker than usual due to high attributes, magic items and spells, the terrain, their allies, or recent events. Good or bad tactics on either side can completely transform a battle, as can party composition. If you don't take circumstances into account when assessing how difficult an encounter will be, you're shooting yourself in the foot.
4) Templates and class levels can produce radically different effects when applied to monsters of identical CR. A mind flayer sorcerer 3 and a half-fiend elder xorn are both CR 11, but the xorn can cast a 15d8
horrid wilting, as well as
blasphemy and a zillon other high level spells, while the mind flayer can only cast
magic missile. I used to think that this made the system "broken" too. (Now I just cackle with glee over the horrid templated monsters I can produce.)
Thing is, you're never going to be able to come up with a system that gives you a precise and infallible evaluation of how dangerous a given opponent is in a system as complicated as D&D. Not in a million years. Not only is there randomness in the system (attack & damage rolls, saving throws, etc.), but since you can't account for every possible contingency, you make the system as robust as you can in as many circumstances as possible. Once they average case is covered, you have to trust that people will be able to figure out the cases where the system produces skewed results for themselves.
I'm not going to claim that the CR system we have is perfect or can't be improved, but it's a lot more helpful than the CR = HD approximation from 2nd edition or looking at a monster's XP award to guess at an encounter's difficulty. It's a tool that was made for an average-strength party of 4 characters, equipped with appropriate equipment for their level. And as long as it's used for that purpose, it works pretty well.
Sadly, most games I'm aware of deviate from the "typical game" that the system was designed for in several ways. Since the only guidelines for accounting for larger or smaller PC groups, more or less equipment, and suchlike that I've seen are the ones I've cooked up on my own and a few notes and sidebars in adventures or campaign settings. Which means we don't get our hands held by WotC R&D, and have to use our own judgment now and then.
Personally, I don't think that's a great tragedy.*
*: Except for CR 3 monsters. What the heck is up with WotC's CR 3 monsters lately? Maybe I've just been reading the wrong stat blocks, but dear lord, the Gravehound and Karrnathi Skeleton are weak for their CR. Okay, rant over.