I believe the 800 was a good size as well. From all the reviews I have read the reason for the increase in displacement was to be able to make the engine Euro 5 compliant without losing hp and torque. Not sure what new demands the Euro 5 specs require, but have seen other engines increase size to meet them as well.
As for all the new electronic add ons, not sure I am a fan of those. Think I would go for the lesser models(non Pro) to simplify things and less chance of something breaking.
I like the split rad design that allowed them to reposition the engine for better weight balance.
I think it is a good evolution of the Tiger line, but a complicated and costly one.
Like Carl said, hard to justify the big sticker increase when the old Tiger 800s were great bikes.
It's going to be interesting to see how the 1200 Tigers evolve with the new demands for tighter emissions and what Triumph thinks the market wants in their new bikes.