There were far too many instances where one guard would accidentally hit another, and they'd fight to the death while ignoring the original attacker.
I just had to laugh at one mounted guard along the road past Kvatch whose horse got killed, and he proceeded to sit sideways on the dead horse for the next three days. Obviously, with the horse being dead, he never made it to the end of his patrol route, but he kept trying.
:hehe:
The idea behind Radiant AI was good, it just wasn't developed and polished enough in time to be fully effective in OB. Actually, the same can be said about several other aspects of the game: Havok physics were also a huge potential step forward, but poorly implemented in a number of respects. I would tend to suspect that making one or two major advances between games is about all that can be expected of a developer, otherwise you've got too many things being redesigned at once with no guarantee that they'll work as intended. Problems with any one of those aspects can impact other features and scripted funtions as well as quest design, which then need to be scrapped and redesigned around the reduced capabilities. If the problems are apparent early enough, you can fall back on existing technologies and still finish the game properly without the shiny new features, but if it happens later (as apparently was the case with OB), there isn't enough time to either fully solve the problem or to properly redesign everything which relies on it. You get something that sort-of works, and sort-of doesn't, so it's not "better" than the previous game, just "different".
Yes, for Oblivion, they did bite more than they could chew: RAI, Havok, NPC schedules, big quest lines, better graphics, textures and models, and my pet gripe, fully voice acted dialogs, which greatly handicaps detailed development of AI and quest lines.
As for better AI, and protecting quest lines from misbehaving NPCs.
One solution can be replaceable NPC roles in quests, so if an NPC was killed or otherwise unavailable, (cruising around the world, or in a prison cell), the intelligent event/quest managers, could fill their role with another available NPCs.
For this option, we should revert to Morrowind style dialogs, i.e. without voices or adapt computer generated voices, so that the new NPCs could say the lines that the old NPC would have said.
Another safe guard, would be changing the AI, so when somebody tries to steal an item and get caught red handed, the owner should call in the guards and they should arrest the thief, instead of killing him, and the arresting action should be automated, so if they could catch up with the thief character, the arresting action/animation should happen without any interruption, and the wannabe thief should be sent to prison with a guard.
Another method to help NPC AI is to place hidden local guide objects in specific places and script them to help NPCs in local situations.
These guide objects know about each other and make a guidance network around the world, so for instance some of them help NPCs recover their health points, so when an NPC needs to recover it's health point, it looks for the nearest guide object, and tries to reach it.
The local guide object might not be scripted to help NPCs with health recovery, so it searches the network for another guide object that is flagges as such, and sends the NPC to the nearest one.
The nearest Health recovery guide object, can check the NPC for his health condition and other characteristics, and depending on the conditions order the NPC to take an action that results in his health recovery, for instance, enter the chapel, and kneel before the altar and pray, and so on...
Or sends him to the local healer to get help and so on...
There can be other specialized guide object to help NPC AI in different situations, and some guides can be scripted for more than one purpose, like health recovery, taking refuge/cover, navigation, and so on...
As for navigation, there can be situations that mere path finding would not solve a navigation problem, so for instance an NPC could climb a ladder, and jump to take a hanging rope to swing to the other side of a gap, and jump to catch the other ledge, and slide down over the passing coach and so on...
this all can be scripted over some local navigation guide objects, that with the help of each other guide any NPC who wants to pass the gap of a specific place, but those guide objects could see if the NPC has good acrobatics, so for other NPCs, they could solve the problem in another way.
Conditions like having two functional hands, adequate intelligence, skilled in speechcraft, specific races and so on can be of importance in those guidance scripts.
OK, I wanted to go on, but this was unprepared blurting of some ideas, on the fly, so I have to integrate those ideas into a whole system and offer them in a better way.