Kraydak said:
Designing monsters to be the functional equivalent of 5 ordinary characters has many draw-backs. There are two ways to do it. Firstly, you can just use a more powerful (but well balanced) monster (in 3e terms, use CR=APL+2-3.
Secondly you can have a monster that has many more hp than normal for its "level" and can take more actions or otherwise has a higher offense than normal for its "level" but the basic interaction stats (to hits, saves, save DCs, AC, skills) are appropriate for its "level". Everquest (and WoW, to a lesser extent) did this, in a large part due to programming limitations. It works, much of the time. It breaks *horrifically* if PCs use Charm effects.
A more powerful but well-balanced (by your criteria) creature is not the functional equivalent of 5 ordinary characters. It is the functional equivalent of one such character, though of a higher level. An example in D&D would be an Ogre fighting 1st level characters.
But when we look at creatures with a "higher than normal offence" for their level, things become more complicated, and it is these complications that I believe you are not taking account of.
First, if such a creature has both higher hit points and a single attack that is more damaging than normal, then what we have is simply a higher level "well-balanced" creature.
Second, if such a creature has normal hit points and a single attack that is more damaging than normal, then we have a "glass jaw" creature - see below for my thoughts on them.
Third, if such a creature has multiple actions, it does not necessarily need more hit points to play quite differently from an ordinary creature of its level: in terms of output, 10 actions per round and normal hit points is the same as 5 actions per round and double normal hit points.
Fourth, creatures with multiple actions impose different (and more complex) requirements on the GM. Each Hydra's head, for example, might have its own hit point total to track. We can imagine a creature drawing on multiple power sources, each of which has to be tracked separately.
Fifth, and a reason for having multiple action creatures despite their complexity, is that the number of actions also affects the character of game play. Thus, a death ray dealing 20d6 hits on a failed save is equivalent, in terms of hit points inflicted, to two death rays each dealing 10d6 hits on a failed save. But they play very differently. The second option creates a creature who takes more time to resolve at the table, but who interacts with more than one PC at a time.
I don't see that creatures with multiple actions are a detriment to the game. I don't see that they are especially hard to design well (although the design parameters are obviously different from ordinary creatures). I don't see that they are viable as PCs (for the reasons I have given in my earlier posts). Therefore, we have to choose between two alternatives: either monsters = PCs, or multiple action creatures are possible. I don't see what's wrong with choosing the second way.
As for the charm question, there are a few ways of going. Perhaps Beholders are immune to Charm. Perhaps each spell only affects one of the Hydra's or Ettin's heads. To be honest, if something has to give between charm spells and the fundamentals of creature design, I think it is the charm spells that will give.
Kraydak said:
Glass Jaw monsters (henceforth OMs for Ogre Magi, how I loathe thee) pose several problems. In 3e terms, they are functionally impossible to CR well.
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In addition to being actively hard use as a DM (the CRing difficulty also makes them hard to place reasonably as a DM), they just aren't that fun to face as a player.
The above comments on OMs appear to presuppose that the OMs are solo, or in a group of their ilk. But what about OMs behind meat shields? This is a standard trope of D&D from way back (eg the example combat in the 1st ed PHB, which involves an Illusionist and 20 Orcs). The tactical challenge becomes finding a way to shut down the OM without having to hack through all that meat.
Looked at in that light, the OM is really just a variant on the NPC magic-user. Often, however, it has melee or other potential that precludes it being used as a PC, because this extra functionality would tread on the toes of non-wizard characters.