I personally haven't been able to find out why everyone thought Myth III was so bad. The graphics were awesome, not only the first 3-dimensional graphics in the series, but they looked less pixelated too.
The tons of new units were hard to manage at times, but brought a lot of variety to the game.
And the story was pretty reasonable: just what I'd expect from a Myth game, although it was rather cheesy and the cutscenes were kinda weird. It was pretty good for Mumbo Jumbo having to buy Myth from Bungie.
BE HAPPY MICROSOFT DIDN'T MAKE MYTH III!!!