Continuing from here. I was pondering Pilgrim’s comment that rituals don’t end up being used much.
To some extent, this is actually an advantage of rituals. In previous editions of D&D, every noncombat spell you memorized meant one combat spell you didn’t memorize. The spell lists were full of interesting-to-read but obscure spells that were highly unlikely to see use. For instance, a spell that detect secret doors in a given area. This spell sounds good, but doesn’t help the game much. An adventuring wizard is unlikely to memorize it, since he would have no idea when to use it unless the dungeon just happens to have an area where he knows a secret door exists and is vitally important to find, but for some reason no one can find it. The only real way to use this sort of spell is to find a way to abuse it (spending a month to explore the dungeon, perhaps), or to bump into the rare situation where it is useful, then rest for 8 hours memorizing the spell. In 4th edition, this is simplified by increasing the casting time to 10 minutes but getting rid of the memorization time. If you know the ritual, and you end up in the rare situation where it is useful, you can just use it. Presumably the gold cost is set so that it is very worthwhile to use when you know you need it, and not worthwhile to use frivolously.
So the ritual list does seem to be chock full of practically useless spells, but if they are very cheap to learn, this isn’t a problem game wise. They are useful in very rare circumstances, and once you know them, they don’t take up “space” – they will always be ready when you need them. If they aren’t cheap enough to learn, this would be an issue of execution, not of game design (i.e. you could just make them cheaper).
One problem is that it may be kind of boring if you are set on being a secret-door finding wizard, and the ritual you have for it is almost never useful. But this would just be a case where what you want is not a ritual at all, but an arcane power to find secret doors, something you actually pay for (i.e. sacrifice some other power or ability for) so that it is actually a significant part of your character.
On the other hand, the fact that rituals are a storehouse for colorful but useless noncombat spells may be a bit of a disappointment for the ritual caster. You would have to be very high level before the cost of these obscure rituals is trivial enough to be worth getting them, and at that point you are paying trivial costs to get trivial powers. Fair, but not very exciting. It is nice for game balance that the wizard isn’t using noncombat magic to trounce on all the skill-based characters, but when does he get to use his rituals?
Well, there are a few rituals of real interest, like “Hand of Fate” which tells you what course of action to take. A lot of the other rituals almost seem like they are not meant for the players at all; they exist for color, so that the players can identify them when the DM puts them into an adventure. It would usually be quite rare for a PC to want to create a magic mouth, but maybe the ritual is meant to provide inspiration to the DM to put one in a dungeon, and then the PC wizard can look at it and recognize what exactly it is. Otherwise, though, if rituals aren’t used very often it is OK with me – if everyone is using skills instead, the wizard has just as many skills as everyone else, and is just as exciting (or more) in combat, so everything is good.
One trap I do see with rarely-used rituals is that they have a certain similarity to rarely-used skills, which 4th edition D&D got rid of. Typically, the only way for such a skill/ritual to get used was for the DM to specifically put it into the adventure for the benefit of the player. But this could be a problem in the case of rituals. If the ritual isn’t really necessary, you are penalizing the players by tricking them into spending hard-earned gold. If the ritual is essential for the adventure, you can’t put it into a general-purpose adventure because the players couldn’t complete it if they don’t have the ritual, and that would be bad adventure design. But if you know the adventurers have the ritual and must use it, you would be punishing the players for having the rituals, since groups who have rituals would end up with less gold for other things than groups which don’t have rituals. This sort of thing is one of the problems with spending experience to take actions (and in 4th edition D&D, gold is a form of group experience points).
This particular problem can be solved with the same adventure design used for skills. Using the ritual should provide a tangible benefit, but you can still get on without the ritual. There are only 17 skills, so you can readily account for each one when designing your adventures. But there are as many rituals as they have time to publish. To really balance your adventure around rituals, you practically have to custom craft the adventure for the characters. For a general purpose adventure, you would be hard-pressed to account for every ritual that exists. Most rituals would never see use in a general purpose adventure, but if you are unlucky, some ritual could exist that totally defeats the whole adventure.
This would seem more likely with very high level characters, as it seems the stated idea in 4th edition D&D is that high level adventures are awesome events of godlike beings, and the charaters are expected to have incredible game-breaking abilities. But how do you plan a non-character specific adventure for characteres with stupendous noncombat rituals? If you give them an earthly challenge, they might just ignore it – you give them a mighty journey to go on, and they just teleport to the end. So you can give them godlike challenges – journey to the Xth dimension. But if you give them a godlike challenge, what if they don’t have the right godlike abilities? After all, there is no guarantee they have any particular ritual, or any at all for that matter. Oh well, I haven’t played to that level yet anyway.