You sure have had some pretty bikes Rocker.
I think 670 to 745 cc is enough to make a difference. I would suggest that an extra 75 cc will reduce gear changes and help with the life of your drive chain.
If this article is to be believed, the new motor will have around 12% more torque and 68mpg. HP increase would depend on whether you are comparing to the manual or auto 700 but 54hp is over a 10% increase.
The additional counter balancer should get rid of the vibrations some people complain about.
Improved acceleration and improved mpg sounds like a good move to me but I won't be running out to buy one for a while either.
2013 EICMA: 2014 Honda NC750X ? First Official Photos and Specs
In the end, anything and everything they do is to increase sales and grab market share, right?