I didn't want to make my last post too large so I decided to include ideas for AV5 in this post, in no particular order.
Move far enough forward in time or to a new area in Avernum for all old plots to die a complete death.
Create magic system that has elements to it that can be countered or nullified by another element. Same with the divine based magic. Each type of magic should have an opposite and equal force that balances it. If someone can cast magical damage at me, I should be able to shield myself/others from it, reflect it, absorb it, etc...
Each magical spell/ability should be learnable by the playing characters. No magic should be out of the range of understanding of a magic user of same type or class. (for ex. crystal worms using mind control that you (as a mind control expert) have no way to learn or defend agasint, this shouldn't be in an rpg game).
There should be different types of damage for melee, peircing, slashing, crushing, etc... Monsters should have weaknesses that allow a balanced team to depend on one character or another, and armor should have different degrees of protection for different types of damage. (for ex. Leather does not defend well against crushing damage, but plate does).
Weapons and items should be clearly thought out for character advancement path. If I choose to make a character an expert at Bows, but there is a very poor selection of bows, doesn't that ruin that entire character path? Having so many useless items in a game doesn't make sense, the player will never use it or pick it up, so why waste time with it? Its better to hide useless items then to make a player pick throuh mounds of item trash to find what they want.
Allowing people to make super generalized characters that can end up being completely useless should be avoided with an advancement system that is smart enough to understand what type of character your creating. Feats and skill advancement should be rewarded with more advanced feats and skills being tied to your previous choices. Example - I am a thief/archer, I have advanced flethching skill, I should now be able to choose the ability to poison my arrows (since I am an expert at making them). Abilities should be more than just a percentage of a chance to poison a person with arrows, they are abilities and should always be on and whether they work or not should be determined by the monsters weaknesses and strenghts.
Thieves should have some kind of stealth variable, just becuase one of my party can be seen shouldn't automatically make my crime seen. If my thief is an expert at stealth and hiding, the thief should be able to hide and steal something out of sight regardless of other pary memebers visibility. Also, they should be able to sneak up on people in combat.
There should be the ability to use either keyboard or mouse without having to switch back and forth, or to use both (one hand on the keyboard, and one on the mouse). In other words, ergonmics should be considered when designing the interface.
Pack animals! Why can almost every Avernite own beasts of burden but your own characters can't, or allowing characters to have storage areas (or purchase them).
Item crafting! If other Avernites can make wands out of sticks, or potions out of herbs, then why can't one of your characters specialize in that too? I say this within reason, creating kites from string, wood, and cloth is not relevant to the spirit of the RPG or plot, so item creation with a purpose is all I am saying.
Music? I know, it was said its too expensive, or the nice reply of "Use headphones and listen to your own crap" is not a constructive answer. There are plenty of freeware, royalty free music and songs, really... Do you know how to use a search engine?
Sounds could be enhanced, after all, if your not going to go for the "WOW!" factor with graphics maybe you could do it with sound immersion. Hearing the same creature screech and continous dripping looped over and over and over again really destroys any type of immersion your imagination can muster. There are plenty of royalty free sounds, and sounds that have no copy rights, so saying that its a price issue doesn't make sense.
Thats all I can say for now, I got more but I have to get something to eat, lol.