Pinky,Your thinking is just why I researched and wrote my Near Field Line Array white paper. My goal was to establish a structure to what was, at the time, an unstructured state of affairs for line array design. Hopefully, others have benefitted from the guidelines and observations that I suggested. Bottom line is that many people have either built or previously heard line arrays that were not well designed. Hence, they concluded that all line arrays were bad and not worth the trouble to study or implement. My comment is that you really have to hear a well designed line array to appreciate how well they can sound when well designed and implemented.
Finally, I agree with you that a line array is one project that can sound better than the sum of the parts because you can virtually eliminate mechanical and thermal compression via the use of multiple drivers. Hence, you can reduce distortion and increase dynamic range and even achieve sensitivity improvement in the mix.
You just have to get people to listen to a good array to convince them.
Jim