Artoomis said:
Ever hear the expression: "Sometimes the dragon wins?" The game is less fun if some great peril is not faced, and sometimes the PCs lose. They may even lose and not save the world. So be it. Not everything should be pre-ordained to a PC victory. TPKs happen.
I agree completely.
But if a creature was released with an "I Win" ability (instantly kill all PC's, unlimited range, no LoS needed, no save, no SR), then I'd houserule it. Throwing that at the PC's wouldn't be a 'challenge', it'd just be mean.
That's an exaggeration, but MDJ is pretty much in the same category unless the whole campaign is designed around it.
Artoomis said:
This one is NOT broken
It's fine to not use it in your campaign, or to replace it with a toned-down version that gets used more often. These are certainly valid DM choices. In fact, with an atypical campaign that has very, very few artifacts, even minor ones, the risk factor for casting MD goes way down and the spell becomes a bit too strong due to lack of a presumed balancing factor.
The PHB is based upon a world where minor artifacts are fairly common for characters who can cast 9th-level spells (. If your world is not like that, you should adjust MD accordingly.
As explained above, the Will save for an artifact is not hard to make, and if you have a reroll-granting ability, it sinks further. Also, there are too many ways around it:
1: The caster will be exalted in the eyes of his god if he defeats these heroes and has been assured (maybe falsely, but he believes it) that he will have his power restored if it happens to go awry.
2: The wizard is actually a Dominated pawn of or fanatically loyal to the main bad guy. He would give his life for him, and the loss of his powers is a price he will pay to protect his master.
3: The caster is an egomaniac or is a brave / foolhardy enough character to take the tiny risk.
4: He finds out about artifacts the PC's have through divination spells and attempts to remove them beforehand.
5: The caster hates the PC's so much, they're willing to lose anything to destroy them.
Maybe they're not likely, but they're possible. Fufill any one of them and the RP restriction no longer applies and as you described, MDJ shoots back up to overpowered.