Theater Talkback: Flattened - NYTimes.com Maybe it sounds a little perverse, but I usually try to avoid seeing any movies made from stage plays or musicals I have particularly enjoyed. A natural curiosity about how the material has been translated into a new medium tends to be outweighed by a general foreboding born of past experience. Too often the particular delights of a stage production evaporate considerably - if not entirely - in the translation. The past few months have, alas, borne out my commitment to avoidance. For various reasons I broke my rule and caught the movie versions of two shows I adored: the head-banging, hair-band jukebox musical "Rock of Ages" and the stiletto-sharp