"All warfare is based on deception." -Sun Tzu
As fans, we pick favorites. We have favorite heroes, storylines, artists, writers, and villains. If you were to ask someone who their favorite Spidey villain is, you would probably guess the Green Goblin, Doctor Octopus, Venom, or Carnage. There are lesser, yet still respectable villains, and there are those at the very bottom that should have stayed in school and off of drugs. Kangaroo and Spot would be examples of the last type. Actually, Spot had a pretty decent story in Amazing Spider-Man #589. That brings me to my point: any character can be interesting or a threat to the hero, if they are well written. Mysterio and Chameleon may be average quality villains, but with a writer that respects their abilities, they could be shown as greater threats.
When I read the Sun Tzu quote, I immediately thought of Dmitri Smerdyakov and Quentin Beck. Smerdyakov may be a foreign spy, terrorist and saboteur, but his M.O. has been deception since day one. In fact, his training by a hostile government to attack the United States makes him all the more dangerous. He has failed against Spider-Man so many times because he works alone, and without sufficient backup and distractions. Chameleon's best successes have come when he has posed as someone else and lets the fights be handled by stronger criminals. In his own words, "Let's be brutally honest: I was never your equal in strength. But in cleverness...in deception...that is where the Chameleon shines!" (Spectacular Spider-Man #242)
Sun Tzu was a proponent of manipulating an enemy's perceptions to both win and avoid warfare. Illusions are still used by militaries thousands of years after the Chinese general's death. "Misleading one's adversary about the nature, size and location of your military forces--and disguising your tactical or operational intentions--has been part and parcel of military strategy since it's inception," says William Casebeer, research manager for human systems and autonomy at Lockeed Martin's Advanced Technology Laboratories. Such tactics were used in World War Two by the Allies to fool the Nazis into thinking their forces were larger and stronger than they were. In the 1850s, the French used magnets to fool Arab cheifs into thinking they had magic powers. Illusions such as these, admittedly from a more technologically advanced position, are exactly what Mysterio does best. Granted, Peter's spider sense tends to guide him through Mysterio's illusions, but Beck has had the ability to dampen his early warning ability since their first encounter. It is the fault of the writers to not utilize that advantage in various stories.
Maybe fans are too focused on physical battles. Maybe cloak and dagger (no pun intended) style stories dont interest readers. Personally I would enjoy seeing Spidey take on a political thriller style story with an enemy that uses illusions and deception. Mysterio and the Chameleon have had the makings of great villains for decades, but have been left behind as second rate. With a little tweeking, they could be given stories that would be talked about for years.
All of the info on military tactics were taken from the March/April issue of Scientific American Mind.