Performance per watt is exactly the problem. Apple is focused on thin and light to the exclusion of all else, which then drives smaller batteries, which then drives lousy performance. These new machines should have been the 13 and 15 macbook's, and then had a high-performance pro in the 2015 form factor.
How many people actually have thunderbolt 3 devices that can use more than USB 3.1 bandwidth? Essentially none.
The GPU is a minor bump over last year, and falls at the bottom of the pack for currently available options. The SSD is important because it'll improve swap speed, but RAM is still a bottleneck. The CPU performance itself bump is minor too. Screen color gamut is nice.
The net is that it's a collection of minor updates with minimal practical performance improvement, a gimmicky touchbar that damages usability (keyboards work because of muscle memory - to use the touchbar, you'll have to move your eyes from the screen - at that point, the net user performance is similar to using a mouse), and a price increase.
It's the combination of those things that has caused the outcry:
1) Mediocre performance improvements
2) Need for multiple dongles (I count 6 for me)
3) Price increase
Remove any one of the three, and it'd be just the usual griping. The three combined show Apple's arrogance continues unabated.
There's much better hardware - on any spec, or collection of specs - at a lower price point. If it weren't for the monopoly on OSX, and the fact that we had essentially no updates for three years, Apple would be looking at a failed launch. But because they neglected the mac line so long, and the alternative is windows, they have pent up demand to make it a success. I hope they realize though, that they pissed off many of their longest and most loyal customers by focusing on the mid to lower range customer.