1. Monte Knew about 4e and possibly even helped write it a bit... This is a "secret" playtest.
What better way to explain why suddenly a prosperous company like malhovac was suddenly dark then to say he decided to shift focus into writing fiction? But, why make it all secret? Why not just say I'm playtesting 4e?
2. Monte is upset at the current tactic of bashing 3e and saying 4e will fix everything this faulty game did wrong... His version...
He's attempting to show how "his" version isn't as horrible as it's being painted, and with just a few tweaks can pretty much be the new game. But he's never struck me as the type to take things too personally before...
3. The currently crew, some of them his friends, asked him to sort of hype up the changes... Show how it works well without literally saying he's playing 4e... If it's good enough for Monte, it's good enough for anyone right?
But that seems somewhat shadowy conspiracy...
4. He's flexing his creative muscles...
Once a game designer, always a game designer right? Also everyone houserules... he's just more in the public spotlight. Plus he knows the system and knows how to mess with it.
In truth, I think it was some combination of the above.
Maybe he knew roughly when 4e was coming. He timed his "opus" to make it out onto the shelves with enough time to do well in sales, and then jumped out of the game so as not to waste time money on products that might not sell (once 4e was announced) and moved into his writing game...
Now he's having fun playing with rules that are somewhat similar to whats being said about 4e (or what WAS said about 3e long ago.) and seeing what they'll do...