Even Nokia was going to start releasing Android phones. Full Android.
They saw the writing in the wall, but they got Elop'd.
The moment Nokia was sold, WP technically died for real.
I still don't ascribe to the Elop = Trojan horse theory.
The company was failing long before he took the reins, the rot had already set in. Meego was never going to catch on significantly (and I'm a huge fan of it), Symbian was pretty much already dead. Android may have been an option, but with little liquid capital, Microsoft promised them profit (through subsidisation). It's easy to see why they took the offer - and even today, you only need to look to HTC and Sony to see that quality /= sales. At least Nokia still exists in some form today, and is profitable. They paid a hefty price for not diversifying enough, but that's not on Elop. If you go back, decision by decision, every move he made is logical and justifiable.
Also worth noting that he got a fucking
incredible sum from Microsoft for Nokia's mobile division. That $9.4b, which is looks a larger mistake for Microsoft by the day, gave Nokia the cash they needed to fully re-create itself (again) through the Alcatel-Lucent buy-out. But who started that ball rolling? Elop, in 2013 - when he bought out Siemens' share in NSN.
Very few tech companies are able to successfully change tack. I'd argue that, partially thanks to Elop, they have been able to do just that. I don't think they'd be in as good a position right now if they were still pumping out Android phones, the margins don't exist for any company not named 'Apple'. They have the brand-licensing going on now too - all of the profit, none of the risk.
Ultimately, everyone who leaves WP comes back, so I'm gonna say anyone who likes good UI loves WP. I can't even leave because I know I'd be right back haha.
Android's UI is actually pretty decent now. And Windows has gone backwards ever since 7.5, maybe even Zune HD, in my opinion.
Also, if you love great UI and can deal with very few first-party apps, I implore you to check out Sailfish. Absolutely gorgeous to use, puts everything that isn't BlackBerry 10 (which is basically abandonware now anyway) to shame.