you ll have no strength or muscle. i for one would rather have good strength levels as well as good cardio fitness.

if someone went to the gym, warmed up with 10 minutes of cardio, hit the weights(properly) for 30-45 minutes, then finished up with 20-30 minutes or interval cardio and yoga based stretching, that would be a much more complete workout

ftiness has 3 aspects really: strength, endurance, and flexibility. to neglect one or more aspects is pretty silly