Not trying to be arrogant, but "it also might be worse than what it replaces" won't fly. Ive sat in one. I've driven one. I talk to a handful of the development engineers on virtually a daily basis. Scott (our head calibrator) has too.
It is as good or better an engine than the 6.4L. Yes, there is more emissions equipment. All of which are revised designs from what is equipped on the 6.4L and are far less prone to failure. The SCR is the only unfielded component, but has undergone a very large amount of testing.
The 6R140 transmission is physically stronger than the 5R110, and when calibrated properly will handle power levels that the stock 5R110 hardware will not.
It has an air-to-water intercooler. It has a VGT turbocharger with a mechanical wastegate. It has a 4-piston common rail injection pump. It has heads the size of a small house anchored to the block with the force of GOD and other design implementations that I could only WISH showed up on the market years ago. The 2-piece crankcase design used is even stronger than what is currently used in the 6.0/6.4L crankcases. The compacted graphite iron crankcase and alloy aluminum heads have very advanced metallurgy that you won't find anywhere else currently other than some of the higher end european cars.
Peak tuned power levels will be comparable to what we are seeing with the 6.4L (with totally stock parts) with, IMO, enhanced durability. Small bolt-on parts will *perhaps* make it even more capable.
When all aspects of engineering are looked at objectively (power, drivability, emissions, NVH, ect) there has not been a step backward in any progressing generation of the Powerstroke. 7.3 < 6.0 < 6.4 < 6.7.
The 7.3L has a garbage lower engine design (by today's standards) and a garbage injection system. The 6.0 has a garbage injection system and an emissions system with no durability. The 6.4L has, at worst, a questionable emissions system. The 6.7 for all practical purposes has none of the forementioned issues.
So to address your statement, yes, it is amazing.