I personally preferred the abilities of Diablo rather than Diablo II. Spells likke flamewave and town portal made the game easier. I especially liked some of the Skills that the characters had like the ability to fix an items durability or pick traps when you needed to.
Some of the abilities in LOD were alright. For instance the Golem was MUCH better than in the original and the introduction of ice attacks or transformation were pretty cool.
I think that in the Third installment they should allow the user to create their characters a bit more like baldurs gate but with the good old diablo feel to them. So you could create a Mage and choose their gender aswell as being able to modify certain aspects of their abilities and give the character a certain amount of points to give to strength and so on.
Some of the new abilities I think should be put in D3 are
- Maybe some sort of Smithing/fletching skills
- Some time based skills for single player
- The ability to possess/become another creature would be pretty cool
- And it would also be pretty good if they put some kind of combo attacks into the game, even if with a few characters. e.g. Bone Prison followed by a meteor.