However, they do have a LOT of work to do before final. I don't think they will manage. I'm not speaking about bugs which I think will mostly be solved. But the user interface ... the user interface is different in almost every microsoft applications and then every third party application has it's own interface as well.
Swipe left to delete in e-mail: this should simply be an option when developers create a list. Every list where this can be handy should have this option. Sometimes there's a hamburger (sometimes left sometimes right) sometiems there's 3 dots at the bottom, sometimes everything is ordered in the windows phone 8.1 "sliding menu" fashion and sometimes to get into extra options it is "press and hold" an item.
Really this is just a mess. Android isn't very good at this either however they are working on forcing uniform applications whenever possible. Apple is the best on this. It just annoys me that you have to learn 4 different interfaces. I means simply looking for the "settings" is always a search, will it be here or here or there or somewhere else.
UI tends to be the magic sauce in an application, and a smart phone OS is (in some ways) a big app. On desktop, you have certain standards, you see it in Windows, Linux, Mac, menu at the top, File has Save/Close/Etc, desktop, recycle/trash. Those weren't always standards, but neither were mice. Once the mouse became common, you saw UI evolve to the point we see it now.
Smartphone UI is still evolving, and a standard hasn't emerged. It's getting there, but you're going to see experimentation as companies try to distinguish themselves, then they might get knocked back by user backlash (ie. Windows 8's UI).
As for Hamburger/three dots, I believe the standard MS is going for this time around is Hamburger, but there's a lot of 'if it ain't broke, don't fix it' going on. They're probably working on the big fires first, then they'll get around to standardizing menus. (ie. Windows 10 context menus have been slowly getting refined.)
For 3rd parties... well, it's anybody's guess. You see some jumping from Windows platform, some testing the waters as they get into it. Once you see MS's UI standardize and settle down, others will begin following their pattern more closely. Some smaller devs will be waiting for clearer tutorials.