As someone who owns an Xbox One but still ends up gaming on my PS4 twenty times as much, it really does all come down to the exclusive games. I'm relatively content with the other aspects of the Xbox brand, though even with the latest improvements I still find the OS irritatingly sluggish at times.
As someone with a fairly substantial backlog that I tend to ignore in favour of whatever multiplayer game I'm obsessed with at any given point in time, Microsoft need to deliver exclusives that really stand out, either in genre or in quality. There are simply far too many great games this generation for me to bother with ones which seem merely good, like Sunset Overdrive or Quantum Break, and I feel significant franchise fatigue with each of their pillar franchises - Halo, Forza, and Gears of War. The PlayStation 4 is my primary console, but even if it wasn't, games like Uncharted 4, Bloodborne, and Horizon would get me to turn on the box. Games like Zelda, Smash, Splatoon, and Mario Kart get me to turn on the Wii U. Microsoft simply haven't put out a game this generation that sits alongside any of those titles, in my opinion. They have to fix that.
I don't personally care if I ever play another Halo or Gears game. I used to care about both franchises, but we're closing on ten years since either franchise has been at its best. That Microsoft's primary focus is still on these two franchises (plus Forza) irritates me no end. It's such a blatant example of how being risk-averse with their lineup is damaging their brand. What they're doing with Rare is more promising. I think Sea of Thieves is extremely promising, and incredibly ambitious, but I have a nagging feeling that Microsoft are going to poison it somehow. Microsoft also have got to be more careful with the way they go about getting third parties to develop their exclusives. Too many games have been sent out to die which isn't good for Microsoft, the developers, or the gamers. It's always really hard to know exactly why things have gone wrong with these games, but the fact that so many of these third party games have gone awry in one way or another suggests Microsoft are at least a significant part of the problem.
Halo Wars 2 is just the latest example of third party mishandling from Microsoft. Everything about the way the game works implies that Creative Assembly had remarkably little creative freedom, and that instead 343i were making most of the decisions. It has an unremarkable campaign by all accounts, and the general RTS structure is practically a copy-paste of the Halo Wars 1 gameplay. Almost every single change to the way the game works seems to be for the worse. They've reduced the differences between the two civilizations to the point where the Covenant and UNSC feel almost identical. They've massively expanded the Leader Powers features to the point where they feel totally overpowering and laughably gamebreaking in many scenarios. Of course, they also decided to add a casual-friendly Clash Royale 2, pay-to-win mode on top.
If Microsoft had gone to Creative Assembly, and asked them to make Halo Wars 2, and then gave them some freedom, I think there's a solid chance Creative would have come up with something really interesting. Instead we've got a poor copy of the original, and 343i, experts in making poor copies of other people's games, are surely the reason why.