Highly unlikely. Unlike with the 3DS where the price drop happened far quicker than anyone expected, the Vita has been out over a year in Japan and just shy of a year in the US without a price drop. There would be no real incentive for Sony to do so. The fact that PS+ members get free games every month (and Sony extended the PS+ to the Vita in Nov) is quite a deal as is. (In my opinion that is).
As was stated, the 3DS price drop was very early in the product's life cycle and the Ambassador program was basically Nintendo admitting they **bleep**ed up and overcharged their customers.