Diablo 3's long courtship of players has led to a lot of obsessing over information, and with their recent press event, fans will likely be pondering the newer information we've been given. Some may also be gnashing their teeth.
First, as has been the recent trend with Blizzard products, players will require an active internet connection to play Diablo 3, even in single-player. The reasoning they give is that they want to make sure someone who plays a single-player game and later wants to play online can do so, since Battle.net was formerly separate from single-player games because they could not control for cheats or unfair mods and such. Read: also piracy concerns.
Speaking of mods, there won't be any. They will be against TOS. This includes bots.
Now, for in-game stuff. There will now only be six skills that you can select, and there are no longer any skill points. Along with being able to swap out skills at any time, this means the focus will instead be on which skills you want to use, and which runes you want to put into them (to alter their effects). In addition, you'll only be able to select three passive skills. All these skill slots will unlock as you level (as it was previously, though now the levels are a bit different). There's a lengthier description of it in this write-up and interview over at DiabloFans.
It has also been finally confirmed that the Demon Hunter will have two resource pools to use skills: Discipline and Hatred; as the wizard has a faster regen pool, the comparison people are drawing seems to be that Hatred is similar. Different skills will use the different resources, and as the interview linked above notes, it should lead to some interesting builds where you can use both, or try to tweak it so you use only one.
Then? Auction houses! Yes, two. There will be one based on in-game gold. Then there will be one based on the currency of your region. Stop. Read before seething:
First, the currency auction houses are optional, and there will be a gold counterpart for those who do not want to spend real money. The auction houses will all be player-driven though (Blizzard has no plans to falsely inject items into the system), so how that works out will need to be seen. Blizzard will be taking a flat-rate fee from currency transactions when listed, and then again when sold. They have said its nominal, and that it will depend on region (also, auction houses will be region specific, so you'll only be able to buy and use items from your region). Specific numbers have yet to be given.
Further, hardcore characters? They can't use the currency-based auction houses. No purchasing an item with real gold, dying, and then complaining about the waste of real money. It also gives a community to those who want to avoid what some will see as 'buying power with real money.' However, since they aren't trying to balance PVP, and adding it as a side-feature, that will only really matter in terms of e-peen, which will vary by customer.
As for the reason for providing it, if Blizzard doesn't expect to make tons of money because they are charging a flat-rate? Security. Blizzard acknowledges that people will use third-party sites to make these purchases anyway, so they'd rather oversee it, as it had the potential to not only rip off customers, but lead to problems with identity theft. This way they give the players that option in an arena they control, and for which they are responsible.
Some pretty big features outlined there. Naturally, I believe there will be a certain amount of fan outrage, and I myself feel torn on some issues. As someone who only modded when the game started to feel stale, I am willing to see what happens there. Only online connection? That chafes a bit, because sometimes I really don't want to play online, or my connection is being faulty, but it seems that this is Blizzard's new way of dealing with piracy.
Auction houses? The currency system makes me wonder how it will work out. There will be a certain number of free listings an account can make, which means I may well use it to sell, but I cannot imagine myself using it to buy. Therefore, while I doubt I would ever make tons of money of it, I am somewhat amused by the thought of other players paying for my copy of the game if I make enough (and the bill to my ISP). Since it will be a player-determined economy, however, it's difficult to know how that will play out until I actually see it in action.