The mouse is so vital to WoW that MMO mice have progressively added more and more buttons because it's essential to have your hand on the mouse when in combat.
That's not the 'mouse being vital', that's 'missing out on keystrokes' and putting a keyboard on the mouse.
Actually it is the 'mouse being vital'. It's so vital that you don't "use it sometimes" and float back and forth ala classic mac interface the article discusses. Your hand is always on the mouse during combat.
Semantic games are fun but unless you're actually contesting that the mouse is vital you're just tilting at straw men.
Actually, it's "mouse being required". As in there are functions that Blizzard will not allow you to keybind like turning your camera or character. In games where this restriction is not in play, players have keys to face an enemy or do a 180.
That's not the 'mouse being vital', that's 'missing out on keystrokes' and putting a keyboard on the mouse.