On Monster Power, the new feature that allows players to dial up to difficulty on the fly and reap better rewards, Jay Wilson told IGN that "the goal of the system is to allow players set a monster power level, and the higher they set the level the bigger the bonuses they'll get to magic find, experience and loot drops -- but the harder the game will be. It's a system we've put in to allow players to have a lot more control over the difficulty of the game."
The patch 1.0.5 announcement blog specifically related this to Diablo 2's 'player8' mode, which would bring the ratcheted difficulty of an eight player game to the doorstep of a single player. It allows for a far wider scope of challenge for players at different stages of the game, from Normal to Inferno.
"As the game's been out for awhile now," explains Wyatt Cheng, "we're finding players are stratifying into different audiences. You've got your player who has 1,000 hours played on their character, they have absolutely amazing gear, and they need more of a challenge. And then you have somebody else who just hit 60 last week for the first time because they've been playing for one or two hours a week since it came out and they've been having a blast but they're just rolling into Inferno now. They don't like to use the auction house, they don't read the internet -- so what does the experience need to be like for that person? Monster Power definitely gives us a bit of room to try and simultaneously hit both types of players and everybody in between."
Also discussed was 1.0.5's other new feature, the Infernal Machine, which requires players to find components of an item that unlock a uber version of existing bosses. The "meta-game", as Wilson describes it, is available to level 60 players, and beating uber bosses rewards you with an otherwise unobtainable legendary ring.
On the future PvP patch, however, Blizzard were keeping schtum. Wilson would only go so far as to say they were "focused on making PVP really great", and that while they'd originally hoped to launch the competitive mode this year, they're keen to ensure it's up to Blizzard standards. That means, barring a Christmas miracle, patch 1.1 is likely to slide into 2013.