UWP is effectively a MS-controlled ecosystem within Windows. If this cancer is allowed to gain market share, users lose control over their applications, MS will be judge and jury with regards to what works and what doesn't, and all our machines take the massive step backward into the closed box ecosystem that those losers over at Apple are bound to.
I really could care less about the sandbox and its security. MS has built an OS that works very well today but they keep trying to push their market strategy within that OS and UWP is the worst iteration of it to date. They get more and more devious about it and it is scary as fuck. At the same time, they have been building on an OS that has very specific perks such as its configurable nature, both in hard- and software, and UWP is the one thing that will destroy all those perks in one strike. And all that, only to cater to a silly market strategy that does nothing to further the PC environment, but everything to cater to tablets and mobile devices. As always, security is used as the cover for pushing more control over the customer and the user, just like governments use terrorism and child pornography to reduce or remove civil rights.
UWP is of the same caliber as the dreaded Windows 8 Metro UI release, it's just a different tool for the same purpose. One Windows. One MS Store. One race to the bottom. They really do love taking one step forward and two steps back, just when you think they saw the light with Windows 10, they launch UWP and they do it with a level of arrogance that we know all too well. If this was really 'for its users' then it would not be enforced, it would be offered. Right now, this is just MS changing the rules of the game when the majority of its players have already entered it. The timing of UWP's launch and the state it got launched in, says enough. In the meantime, actual products that actual users paid actual money for, work like crap on it.
Now what they *should* do, if they want what people in this thread state UWP is for, is keep improving and keep monitoring Win32 and its security. That is all, and it means doing some work for nothing more than the continuation of a near-monopoly on Operating Systems. Apparently for MS, this is not enough or too much work. UWP is a solution for an imaginary problem and a vehicle for pushing a market strategy.