To Quote the self styled "super villain" Megamind; "The difference between a 'good' villain and a 'super' villain is. . . PRESENTATION!". So be it, an evil temple. Always a 'good' idea, and lots of fun for 'good' characters/players to defeat. But. . .'great' characters/players always remember 'great' ideas for which dungeons are based around. So don't "sell" it to them cheap. Demon worshiping, drug using, flesh sacrificing, Spiritualists get remembered (and mercilessly beaten) while evil clerics are just "C7, LE, AC4, HP25, etc... The point (over-done though it may be) here is, throw in some adjectives, some color, something to remember you by. Think Slaughter House, Wicked Hostel, or Vial Shrine. Please don't think I'm being rude or disrespectful to any one, but I find that sometimes I get "lazy" when I'm filling in the spaces of my larger campaign with side dungeons ('small crawls' as we call them) or diversionary encounters and ease off of the creativity. Sorry to use so many words to make so small a point, but it is an important one that I feel strongly about and constantly try to work on in my own game. Consider applying this line of thinking to your interior design as well. Colors, textures and smells are always important, but so are placement and function. Whose to say some paranoid evil priest wouldn't put in a few extra doors for security, or take unusual or extravagant measures in his designs (like putting door handles on the opposite side of the door from the hinges to fool heroes into pulling when they should push). The devil's in the details.