In the last 2 campaigns I’ve DM’d Grease has been one of the most effective spells the players have used, especially when combined with the Sculpt spell (which changes the area of the spell to 4 x 10ft cubes). Combined with Glitterdust, I’d say they were close to the 2 most effective Arcane spells in both campaigns, even when the PC’s were in the mid-teens level-wise.Several combats were turned into cakewalks due to the enemy being greased and blinded. If he fails his save he’s on the ground, reducing his melee AC by 4 and his attack bonus by 4. So he’s easier to hit and it’s harder for him to attack back. If he passes his save, then chances he doesn’t have 5 ranks in Balance and can be sneak attacked. Add to this Glitterdust, that blinds on a failed save. That drops his AC by at least 2 (more if he has a Dex bonus to AC) and gives everyone a 50% miss chance (assuming they can figure out what square the attack came from).
So you can see how the combo is horribly effective. Yes, they are low-level spells, so the saving throws are lower. However, if they PC has an INT of 20+ (fairly likely by the mid-teen levels) and taken a feat to increase the DC for spells from those schools, the saving throws are likely to be in the high teens, which is not that easy.
Of course, much of the problem is caused by the fact that as a DM, I seem to roll poorly for saves for the bad guys! I don’t know what it is, but it seems that when it comes to saving throws, the dice suddenly hate me.
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