The ifixit teardown makes the machine look like a real mess inside, but I think drastically simplifying the connections to all external add-ons and the continued focus on the bottleneck of storage speed give reason to be optimistic about what the future holds.
Macbooks have had available SSD's for awhile.
When it comes down to it, a bunch of sacrifices were made to make this Macbook thinner, which simply is of very little benefit to professional users. It's nice, but not when it comes at the expense of performance and usability.
While ridiculous that Apple doesn't ease the transition with more included cables, my house is full of different types of monitor cables, hard drive cables, and iOS device cables that seemed to change every two years. At least now I might get a decade out of the next generation of them.
The problem is that Apple did not simplify the connections. They unified them. The focus on a single hardware port is all well and good, but in this case it's just glossing over the fact that there are a wide array of different protocols that talk over this hardware and not all of the hardware supports them.
With SSD speeds in macbooks being over one GB/s for years I also do not really see where storage throughput is a bottleneck.
For example, the MacBook Air sacrifices performance for extreme portability and decent battery life. The first retina MacBook Pro bets heavily on high-DPI screen for the first time ever in computers, but less connectors and no DVD. It was risky bets, but a vision was behind. This generation of MacBook Pro asks for a lot as sacrifices (CPU almost already a generation behind, no legacy ports, no SD card, limited RAM, no battery life improvement, ifixit scores lowered, no magsafe, no Nvidia GPU, no screen DPI improvement, etc.) for nothing substantial or exciting. I think that's the reason people are complaining loudly, and I think for the first time in the past 10-year MacBook history, it's fair.