Previous Spiderweb games were pretty much straightforward in decision making. You had to do some decisions in quests (who to help, to do or not to do sidequest), but there was a flaw common for all CRPGs: all sidequests were nust-to-do if you want your characters to stay in shape for mainquests. So no real decision here, except for some cases when you had to do sidequest much later after you get it - there you should see if you are able for the task, but it was mostly problem of save/load. So I really take some path only when I ally someone. It feels... Not enough.
Gameplay. Similar system: you decide who's in your party and after that you levelup them on the same scheme of development, no surprises, no second thoughts, all the choice is like "will I rise Endurance now and Melee later or vica versa?" And you'll get either +3% HP or +5% to-hit, you don't feel like you've changed something. Take Wizardry. It had similar party system but then BANG you could change character class and transform him into something completely different. I don't want to say this mechanic is so great but it offers a choice, gives me a chance to think. Avadon will have skills - now that's something.
But all above is just talk cause story and levelup system is already there. I wanted to asks (betatesters, are you there?) about battle system. Is it challenging? Does it makes your brain browsing through possibilities? Would we have something beside standard scheme "tanks tanking, mages and shooters give hell from the back"? Can it be tuned so that enemies have some special skills making us to seek new tactics for every battle? Hope so. Avernum is great game, but a bit monotonous. Hope Avadon will give good changes we've been promised.