Having played like 150+ hours of D4, I would say, with respect, D4 does not deserve to be in the top 10.
It is an ARPG with a strong story well told (rare in an ARPG), memorable characters, a really well-developed visual aesthetic, five pretty playable and different classes, and which in terms of a lot of the systems feels pretty polished - like it has a fully developed transmog system day 1 and so on.
On the flip side, each of those classes basically only has 1-2 genuinely viable, distinct builds, and the item system is a boring chore of constant minor fiddling, and I've never played an ARPG where drops felt less consequential, and less exciting except D3 before it got fixed. Compounding the issues there are that the paragon path system is absolute alpha-tier trash, which feels like something that wasn't even 1/3rd developed, but got made live because they hadn't got anything else. The lack of distinct icons, the incredibly poor board designs, the general extreme blandness of it all screams "unfinished system" rushed to production. Hopefully it's replaced entirely at some time.
The ugly though is that it's just boring at endgame. It's the most boring ARPG I've played at endgame, and I have a very high tolerance for boring ARPGs normally, you should have seen how far I got with early Warframe or Path of Exile. You're just running Nightmare Dungeons over and over, and only doing other stuff as "required chores" or occasionally when you save up enough currency-ish items to buy an attempt at a boss, which feels pretty crap, because of how they've positioned it in the gameplay.
It also has a pretty insulting and hilariously overpriced cosmetics system that has been in since day 1, and seems highly inappropriate in a very full-price game ($70 minimum), and which will have regular expansions which appear to be at least $40 if not $50 (I imagine there will be a $70 edition with the base game and the expansion, to help new people join). By regular it might be as often as once a year, too.
Give it 2-3 years of development, and the developers redoing the itemization and item upgrade systems, and entirely replacing the paragon/glyph junk, and I think we could have a truly excellent game, but right now? < fart noises >
As an aside, whatever one thinks of the dang JKR, the Hogwarts game should not be on any list of best games of the year, not even as a runner-up. It's an incredibly mid game, with zero innovation. No innovation is fine if you perfect a genre, but it's just low-grade Ubisoft style deal, with terrible combat and weak everything else. The only reason to even put it in a list of "best games" is sales, but the sales were not due to it being high quality for anyone but a serious HP aficionado, and even for those it's basically a guided digital tour of Hogwarts, competently executed as that.