Dan & Jaded,
count me in as 'pro-LOS-tool'.
BTS: nobody is forced to use the tool (c.f. nobody is forced to use fog-of-war OFF option), and in some scenarios it would increase playability a lot. My last game was an operation in which I was attacking a big hill surrounded by many small hills and many small patches of wood. The defending Panther and JadgPanther found a great many openings in the LOS of which I wasn't aware at first (most were situations in which the LOS was over a small patch of trees) that I felt quite frustrated with the close-but-not-really WYSIWYG world of CM. Great game, though!