Alright, you might be wondering what I mean by "Interactive boss fights", what I mean is that I want there to be more to happen during a boss fight and what you do can affect what a boss does.
Let's take a scenario, this involves boss X. You go up to X as a barbarian, your character takes over and a little screen (The same as the barbarian talking to Cain) pops up, the boss then proceeds to ask you a question of how you'd like to die (This is just for how the fight goes, not meaning how you actually die) and you can choose say... swiftly and painlessly, slow and painfully or some others.
This will lead to how the fight goes, you can only pick one, this could bring more replayability to the game, having to start a new character but you know you can pick a different sort of fight for the bosses, rather than "Walk up and attack". These scenarios would not be random, but there could be 2-4 different ways of fighting a boss.
Another option for a boss fight is that you are forced to flee, as a boss may have turned invulnerable for a short amount of time (Think baal summoning minions). This would involve having a long path which the character would have to run down, spells would be disabled for this time as you run, you may jump over logs or go up ladders quickly in order to slow the boss down.
This option may also be available to quests, you meet an NPC, gain a quest (Let's assume that's how quests work) and as you go to where you need to go, you have the option of doing one thing or another, you could save an NPC and gain them as a vendor of exquisite items, or you could leave them to die from a massive demon monster killing them (The NPC may be tied to a pole for a ritual sacrifice) and then you can go loot the body afterwards and maybe get 1 exquisite item for free rather than having the vendor.
I apologise for my spelling and/or grammar as I am very tired with the flu. Hope you liked my idea :]
Having a conversation with a demon in a hack'n'slash game (ie., mindless fast-paced killing) doesn't seem to gel.
Everything is relative.
http://laserblue.org/Lithium -- Diablo II related project.
ftp://laserblue.org -- Stuff.