Groove could be good, its just way to simple. Its almost as if Microsoft doesnt want to be good at these things.
Photo viewer... as a 3d artist professionally, I just want to say I'm embarassed by the photo viewer. Its fucking useless. It doesnt even pan and zoom well. I never thought something could be worse than groove ;) I actually like and use Groove now but the photo app is fucking dead to me. It seems like it has actually gotten worse and yet it hasnt recieved any new features at all. How is that possible?
Now for your other ocmplaints....
Some of the UI design is getting sloppy but its ok, they're trying things. I have faith in the design team to get things right. After all, windows 10 is a pretty decent UI... if only they could unify it finally. But its a huge work in progress and its going to be for some time. This is a good thing in my eyes becuase it means they're going to continue to refine it.
NOT all of the new "features" are party tricks. The most recent build feels pretty snappy actually. They are not just adding trinkets to the windows experience each release, they are also working on the core and performance. Its why they recently created a PCI bug and broke DTS encoding again. They're doing more than just tacking on a notepad so give them a break. You just dont see some of this stuff bragged about in release lists unless it solves a direct issue people are vocal about.
As a Wacom pen user, I dont find windows ink to be a party trick. I find it to be extremely important to the core windows experience. Its nice to see Microsoft taking pen seriously. Its probably because they own N-trig, have the Surface Products and Pen... and are working with Wacom again on a universal Pen. I cant stress how important I feel Pen input is, as an artist that has used Wacom pens since they were invented. The greatest thing about windows 10 is how versatile its ui is. Granted there is work to be done but they are heading in the right direction and seem to be making progress.
Now to get to the keyboard. Yeah. Its garbage. The windows 10 software keyboard needs to be replaced with a swiftkey keyboard immediately, and not the phone one... a new one designed for windows 10. It has to be the ultimate keyboard. There is no excuse now. They have the people to do it. I'm guessing its only a matter of time before we see it and we are likely to before Redstone is finished. If Microsoft releases Redstone without a new software keyboard i'll be very disappointed as a Surface Pro user. I'm sure its coming though. Its just a matter of when.
Microsoft has to catch up in a lot of areas but i'm certain the work is being done, its just not ready. MS doesnt have the luxory of time but they do have the best focus in the industry right now I feel. They seem to be more ambitious than ever.... but then there is the photos app.... oh the fucking photos app. :) It negates every ounce of hope I have ;) Joking. sort of.
Lets stay positive though. Look at what Apple is doing... its boring.
;)