Both games have very interesting features:
- Incredibly polished combat system. Control responsiveness is really great and it shows it was one of the most prevalent interests in the development process.
- Healthglobes are a really great evolution over mindless pot spamming in D2, specially considering their potential value in conjunction with certain passives.
- Great resource systems. The way they balance resource spenders and consumers is just great. You have to screw up really bad to feel resource-starved, which adds a lot to the game's overall fast pace.
- Extremely flexible skill system, allowing you to literally change the whole playstyle of your character with a few changes. This truly encourages experimentation. It would be great if they expanded on the customization options of this feature.
- Individualized loot, simply because it allows you to focus more on the action than on getting ninja'd by someone else. I really hated that in D2, specially in Baalruns, and i'm glad they changed it for D3.
- Incredible item customization and depth. Being able to work on polishing items is really cool, specially considering you can turn a turd into a diamond if you put enough work on it, without sacrificing the inherently addictive nature of RNG (gambling), but working with it. The fact currency itself is tallied in the amount of attempts you have at modifying your items in different ways is just phenomenal. Certainly more exciting than grinding for gold, or farming 920387509823725 terrible items before finding a single one worth keeping.
- Grim environment, really good music as well. Art direction with certain monster designs could be more polished, though. Some monsters just look stupid (those mermaid tentacled things, for instance). I love the fact they add grit through normal maps on their textures, I don't understand why Blizzard never uses them. They could be more polished, but they really nailed the environment of an unforgiving and cruel world.
- Cutthroat league, just because open world pvp has always been fun.
- The passive skill tree, because it doesn't force you to pick useless talents just to acquire a specific big talent, like it was in D2. Every talent remains relevant for the rest of your character's life. Merging both stats and talents in a single tree is a cool solution, although i wish it was a bit less unforgiving with respecs, specially for newbies, but once you get the large picture and the hang of the skills and character specialization, it's really fun.
- The world feels alive, specially when you see other players running around in town areas. Even if you don't interact with them, it's a great feeling
What i don't like:
- Itemization is just horrible as a product of the loot being tailored to sustain an economy and not to provide an enjoyable ingame experience. Sacrificing that "ohhhhh shiny" feel D2 had for raw profit is simply unforgivable. Loot is awfully bland and uninspiring, and overall loot quality is simply appalling. They really have to step up their work in this particualr aspect for the expansion.
- Lack of content. For a 2012 game, the game is absurdly short. The game should have lasted like 20 hours on it's first playthrough, but it barely lasts 6, if you're reaaaaaaaaly slow.
- Lack of pvp, one of the biggest drawbacks this game has. I still don't understand how could have they released it without at least basic dueling, which we're still waiting for. Even if i'm not a hardcore pvp player, i really loved those duels for the lolz back in D2, regardless of how simple the setup was.
- Ingame currency being sold for real money. This is just a straightforward detriment to any ingame efforts to progress in a legit way. If someone doesn't have the time/will to grind in a grinding game, it shouldn't be an option to sell that potential by real money. Selling items isn't great, but isn't as bad, considering good ones can be extremely rare, but gold drops everywhere. This is one of the biggest mistakes they've made with this game.
- Combat feels extremely sloppy. Sometimes your character would just slash the air for no reason, consuming your mana, which can be quite frustrating when you begin and can't afford to just spam your favorite skill. Targeting sometimes is quite frustrating as well.
- Sound effects, specially for certain mobs. Kinda odd considering how immersing the music is, so i really wish they would make them better.
- Zoomed in camera. It just feels like you're way too close sometimes, which can be annoying.
- Monster design. There are some that are really awesome, but in contrast, some are really lame and unimaginative. Some of the models seem awfully unpolished as well. Those little crabs and the siren octopus things come to mind.
- Character models. They just feel like some random model taken out of a generic humanoid library, including npcs.. Animations are also quite bad sometimes.
- Ingame rooms, through the notice boards. Great feature to link single player with multiplayer.