let me start by saying i LOVED the first game, not as big a fan of the second, partially because:
the first game had that spooky atmosphere, the consistant setting, and the lack of over the top crazyness that the second one had, you werent some epic hero from the start, and it had those mild survival horror overtones, you conserved charges, potions, and TP scrolls, you didnt wipe your ass with them. the game went from the church, to the catacombs of the church, to the caves underneath the church, to the mildly cheesey hell which just happened to be located underneath the caves. it felt logical and like you were actually DOING something, not randomly placed in some plains(BORING, more crumbled towers and graveyards, less monestary and OMG THERES A ROCK! i just pissed myself i was so scared), then a dessert, then a jungle(wtf?) then randomly hell. the transitions seemed sudden and with only a breif cutscene inbetween the two, some of the areas were extremely cool, but they didnt really conjure up that same spookyness factor that the first game had, and the big point here THE TOWN, there were no 2D idiots, they all had stories that werent all entirely cliche, and it felt sorta real, they all had their problems, not "oh yeah, im the blacksmith here at the top of the world, im a little better than that angel dude gaurding the entrance to hell despite the fact that im a barbarian and my forge is outside. i also have advice for you, the epic hero who was just off killing legendary shit in hell, just like everybody else. yeah, maybe ive been outside town whacking stuff with a stick, but im not going to help you because um... just fucking buy something." in the first one IIRC the blacksmith didnt go down and help you because he had a damaged leg, the town drunk was... the town drunk, the healer was a healer, the witch was just there to make a buck and everybody else was just a normal scared shitless villager. theres also the whole boss thing, but that has been mentioned many many times. for the most part the second game just lacks that spark the first one had, its kinda hard to put my finger on some of it
summary: better developed round characters good, consistent enviroment good, survival horror type gameplay makes shit scarier, fewer bosses, you dont really get much emotion out of it if they are introduced and die within the space of three minutes then are never mentioned again, seems very arbitrary, spooky atmosphere good, mystery good
changes from both games
farming, get rid of the need for it, make useful items purchasable, or perhaps an elder scrolls style enchantment system, if i want +10 fast cast rate or +1 to frozen armor, why the hell cant i just make it/have it made?! im a level 99 sorceress sitting next to a level 99 necromancer and a level 99 paladin, talking to some dude who makes magical weapons for a living, and i have literally more gold than i can carry!
liked the spellbooks, but then i mostly played the first game single player(90%sorcerers) and nearly all my multiplayer characters were warriors or mundane rogues, maybe some hybrid system, as in "some skills are books, anybody can learn them provided they have adequate INT (still making a spell-slinging warrior possible, but than optimal) and other skills (clay golem amplify damage leap, whirlwind, fucking hammer, just about everything proposed for the new wizard)go on a tree-type system, or perhaps even a WoW type system (ok youve got the skill, and if you want to spend the gold you can make it go up as you rise in level, but you get X points to specialize) to to summarize that: a VERY WoWesque system for class-concept specific skills, such as a necromancers summons or a druids shifting(the whole going up in level as you do, but still allowing specialization, perhaps even a VERY similar re-spec system), alongside a diablo 1 style system for less themed skills with requirements, perhaps have smite available to anyone with a high STR, and heal or fireball available to anyone, provided they have sufficient INT, perhaps make axe mastery available to anybody, but with a level requirement would make finding books an important event again, but would still allow for unique classes to differentiate themselves, spellcasters would still be doing the vast majority of the spellcasting, but characters would be flexible and every character would be unique.
. I played d1 after d2 so I was sorta mad that I couldn't just click once and hold it so I would keep shooting. So I still got hit like twice which almost killed me. I think there's that shift click thing still where you can just aim it in front of the guy and it will hit him but I don't have it installed anymore.