Regardless of how you look at the paragon system, the multiple classes, the questing or item leveling or what your personal feelings are on the quality of Blizzards content we can at least all sit down and agree that Diablo III was a short game. It certainly had a lot of great points that shouldn't be dismissed; visually the game was a treat and the gameplay was smooth as anyone could ask for. No one had a problem with the taste Diablo III had to offer, there just wasn't a quite enough of it on the plate.
So now we've got a new expansion around the corner, filled with all kinds of new goodies for us to look forward to. As of now we know the expansion, Reaper of Souls, adds a few new things to the game: A new melee class based loosely on Diablo II's Paladin called The Crusader, an increased level cap to 70, new monsters, item transmog, and new randomized dungeons have all been announced so far.
But what's really selling the Diablo series isn't its gameplay or classes, nor it's grind-oriented dungeons. Those are certainly fun but what really makes Diablo such an immersive and exciting experience is the atmosphere. The story of a world corrupted, of the fallen divine and slighted angels whose battles against the unholy cause the kingdoms of men to crumble amidst their wrath. When Blizzard first announced Diablo III fans were more concerned about the atmosphere than the UI or class changes, posting redesigns and edits of screenshots to become darker and more foreboding as they saw was more "˜true' to the originals. They have a fanbase that cares, on almost a fanatical level, about world design in a series that should be better known for its gameplay. That's saying something.
Why not keep the dungeon crawling, worry a bit less about the loot randomization and how it may affect the real money auction house, and just create more quests and subplots? No one is impressed with an increased level cap in a game that allows for advancement beyond the level cap to begin with, but absolutely everyone loses their minds at the even slight whiff of a new Blizzard cinematic. Or at any chance of experiencing more story. Watching the CGI scenes is almost a reward in itself for players, but that isn't the only tool that Blizzard has in selling Diablo's rich atmosphere to gamers.
Ignoring the somewhat bland outdoor desert portion of the game Diablo III's level design was spectacular, filled with a decent variety of enemies across a wide background of interactive environments. Bleak dungeons were mixed with lush tropics, fortresses under siege and the spires of hell itself; exploring D3's world in search of hidden treasure or secret bosses was a large portion of the fun, a sensation that dies almost immediately when you're forced to push through the game in a constant grind with only a difficulty adjustment to spice things up.
Add in extra story, more bits of lore, maybe even the occasional scripted event for the second and third playthrough and you'll have a game that's much more interesting by default with almost minimal effort.
Plotting additional narrative that's enjoyable to follow isn't easy, but it's a better answer to keeping player interest than finding new gimmicks to the gameplay that's going to be completable in under ten hours anyway. Now to be fair Blizzard hasn't mentioned a word as to the length of depth of this new chapter, and maybe they'll surprise us with a game as long as D3 was for a slimmer price.
Anything can still be announced, but when the list of new content provides less detail on world design than a CGI trailer the concern starts to set in. The infrastructure for the open world days of Diablo II is long gone, but if Blizzard can bring us an expansion that provides even greater depth and exploration opportunities than the Diablo III then we may very well be in for a treat.