Just from a business standpoint, say your company is growing by manufacturing and selling a product that the critics are saying is outdated. So you come up with a new design that's current, but it costs 50 bucks more. You're already at the high end of the price scale for what it is. Would it make sense to drop a product that's in demand for an even more expensive one - rather than offer people who don't need those new added features a lower cost alternative?
Provape has a very simple business model. They make a safe, reliable, high quality product - and back it up with excellent customer support. They're not trying to appeal to the cloud chasing crowd, so they don't need to double the device's output. Just having what's considered the indusrty standard feature set, a little more power, and superior build quality and reliability is going to sell the v3.
They've also become their own worst enemy - because what they currently make is so good. They've got to watch the cost of the v3, or it won't sell. And if they cut corners to hold down the cost (like making it out of aluminum, or thinner stainless) they'd probably have a near revolt from the current customer base. After all, if I order a v3 it better be as nice as my previous ProVari.
So about all that leaves is an updated product that continues to do what its always done. Nothing radically different - these guys aren't very radical.