I got a chance to play a bit in the Diablo 3 open beta this weekend. It was interesting and fairly fun, but I'm still on the fence about whether I'll actually buy it. On the plus side, it is beautiful (in a creepy, zombie-ridden kind of way), it has a good story, the visual and audio effects are great, and collecting stuff is fun.
On the minus side.... I'm finding it a little harder to articulate. One big, obvious issue is the connection-always-on requirement. That made things a bit laggy, limits other use of our net connections while I'm playing, and generally has too many dependencies on external factors (e.g. there was a nasty storm for a while in the time I was playing - had I purchased the game it would be extremely frustrating not to be able to play a single-player game if my net connection went down).
On the strategic game design side of things, in many ways it boils down to things feeling too streamlined and limited - essentially issues of lacking meaningful choice. Aside from gear, every character of a given class and level is identical to all other characters of that class and level. While this does prevent 'bad builds', it also removes the fun of figuring out what the good and bad builds are and why. While characters do end up with different gear, that's often more a matter of 'what did I find' rather than 'what path did I decide to take'. I think Magic: the Gathering is actually a good analogy in many ways. Playing Diablo 3 felt like buying a set of pre-built magic decks - there is choice in which deck you play, differentiation in capability when the deck is shuffled, and there is definite skill, interest, and fun in playing a given deck as well as possible. However, for many of us who played Magic the process of designing and building a deck was often as much or more fun than actually playing it. Diablo 3 does not feel like it offers that kind of experience - each class is a pre-built deck.
At the tactical design level a player can certainly choose different builds to play, but because a build is so ephemeral the choice feels less meaningful. Access to new abilities/skills is also purely level dependent, so only the really high level characters have full access to what build customizeability there is. In many ways this inverts the build experience of Diablo 2. In that game builds diverged immediately, with the first few skill points, but at high levels additional skill points had a small marginal effect. In Diablo 3 the initial path of a class is very restricted, but at the game goes on the available customizations increase, and a single new level can open a wide range of potential builds. I can see the appeal of this in theory, but in practice it makes much of the early level play feel like a grind which must be endured to get to the 'real' game.
For the actual play experience it felt like everything just happened a bit slower than I'd expected - perhaps that was my machine or net connection, or perhaps it was part of the design (slower low levels allows more 'room at the top' for items and abilities that speed things up). I felt like I was doing more clicking than for previous versions of the game, though that may reflect on my memory more than the game. However, I did find that picking up items was a pain - it required a very precise click on a small target. Automatic gold pickup was nice. An analagous (not identical) system for items would have been good. Making town portals an innate ability was a good choice. The default zoom level was pretty good, but I would have liked to be able to adjust it a bit - the simple zoom-in level was neat for seeing the design in detail, but too close for actual play. I also wish I could zoom and/or drag the mini-map (perhaps that was possible and I just didn't figure out how).
From a fun-factor perspective, there were ups and downs. On the up side, the secondary character (minion) and tertiary character (town-based crafter) were well done. They offered real choices, useful effects, good flavor, and had satisfying sub-goals. Also, killing monsters and getting treasure is still fun :) On the down side, the process of swapping between skill was a huge pain in the butt and really took away from my enjoyment of the game. One of the things I had a lot of fun with in Diablo 2 was adapting my use of skills / abilities to the tactical situation. Diablo 3 effectively forces skill / ability selection to be strategic. I certainly don't have a problem if other people want to play the game that way, but for me it's a lot less fun. It feels like a really arbitrary game design decision to have removed that whole possiblity of tactical skill choice play space, and even to have severely limited the super-tactical/sub-strategic space (i.e. not changing up skills in the middle of a combat, but easily being able to switch skills around between combats). Also, I found the primacy of the DPS stat of the weapons to be off-putting - it really pushed me towards thinking of the game in very math-y, spreadsheet-y terms (I actually like math, and even spreadsheets, but I'm not looking for either in a dungeon-crawling game).
In the end, I think it's still a good game, but it's not wholly the game I was hoping it would be. Buying Diablo 2 was a no-brainer, and I got many, many enjoyable hours of play out of it. Diablo 3....? I'm not so sure. I'm finding myself asking if that's actually the most fun I would get out of $60, and considering what other things I might do with my time that would be more fun than playing Diablo 3.