Rabbitbait said:
If the players decide to try and disrupt a ritual by reading a book IN THE MIDDLE OF A BATTLE, it should make the battle harder. Yes there is a small chance of it working. That's good, I wouldn't want it to be easy.
Oh, I agree that it should make the battle harder. However, the way that it is currently set up, the Arcana and Religion checks are free and the Heal checks are minor actions. The extra difficulty is caused by the chance to take damage on failed Arcana or Religion checks, and the loss of a healing surge when the challenge as a whole is failed. So, the players aren't being penalized for taking attention away from the fight. Instead, it seems as if they are being penalized for being creative and attempting something that not all players will think of.
Its not as if the characters are locked in. They can choose to stop at any point if it is not working out for them.
While this is true, I think the encounter still sets up a rather perverse incentive. Intentional or not, the message that it sends to smart players is that creativity is counter-productive, and that they are better off just fighting. It adds fuel to the complaints that D&D is turning into a minis game.
I like that this gives another option. I also like that it is not the easy option.
I like the additional option too. I don't like the fact that the additional option has a trivial chance of success. As Simplicity said, it's like dangling a poisoned carrot, and even worse, it's a poisoned carrot that only creative players will nibble at. As a DM, I want to encourage this kind of creativity, not suppress it.
I like some of the suggestions that have been made so far, e.g. giving a small advantage for every two successes made, or giving a bonus to the checks if the player sacrifices a move or standard action. In addition to these, I might scale the DCs for the Arcana and Religion checks so that they start at 19, increase to 20 after two successes, and then to 21 and finally 22 to represent the increasing complexity of the closure ritual.