I post here the thoughs i expressed on the windows insider forums.
I completely agree with the OP and the others in this thread in saying that this will surely be a downgrade to tablet users.
I actually installed the TP on my notebook(i3 3th gen 2,4 ghz,8gb of ram, ssd) and i find it slower in all regards to w 8.1. The laptop feels sluggish and slow to respond, boot time is outrageous. The only nice thing is increased battery life, but if to connect to a wifi i have to wait 15 seconds before the panel opens up, it's not worth it.
Also i'm about to buy a cheap w 8.1 tablet, and after playing around with this build i completely agree. I miss the charm bar on my laptop( i admit i only used it to turn off/sleep), especially in regards to the controls, the quick glance at battery/clock/wifi signal.
The toggles do not work as intended. They are not a single- button solution to quickly be closed and be done with it, and we should like on wp8.1, be able to choose which toggles should be provided.
Notifications about the system once clicked upon do absolutely nothing.
The new small menus intended as charm replacement are completely ugly, uncomfortable to use, and very slow. As a suggestion for improvements, you could have an in-app charm bar, smaller, with less buttons, popping up from the side in a wp8.1 fashion, the same way some options are showed only in the lower bar. And keep the swipe from left to right.
The new windows update is completely useless. You can't select which updates you wanna do and which you don't. I had an update loop where i installed manually the display adapter drivers, and where more up-to-date than those from w update. I was forced to uninstall them and let wupdate install his to solve the problem.
Also, you can't click on updates to go directly to the knowledge base to learn what does these updates do, and you can't select the number either, so you're forced to do an awkward copy-by typing.
You implemented a new control panel removing/transferring(ergo downgrading) functionality from the old one to the new one.
So i'm not going to upgrade my new shining tablet to windows 10 if you don't give the option to have a tablet- only experience. Specially the taskbar should be gone from it.
You nailed many, many things with the ui in windows 8. Then you slightly downgraded them going towards 8.1, but now the direction you-re going with windows 10 is very bad- you are making the same mistake you did with 8, taking away proved functionality(nobody ever said that w 8.1 on a tablet had an UI that did not make sense or wasn't perfect!) and forcing the "new way" as an holy grail.
Please heed our pleas. Please do not make the same mistake again.
You tried to make a tablet interface and shove it down the throat of the desktop users. Now you're doing the opposite. Please stop.
And since someone from microsoft is reading this post, i add a general advise for all the platform that you really need to work on: loading times for the apps.