It is hard to compare the 2 types since there is a 20 year difference in technology. It will be interesting to see how the V8 compares to the G2. Still not apples to apples since it is two different mfg's with different philosophies
The only draw back that might be an issue is the late in life serviceability. Most of the extra, ultra light castings used in the automotive industry are not rebuildable. Does not matter if it is a coated or a sleeved cylinder.
As far as output is concerned the torque curve will be the main factor. Not just the peak numbers. Two strokes are notorious for having good midrange torque. The ratio for displacement from 4 to 2 stroke is 1.7 to 1. But that also depends on the cost factor and service life expectancy.