AI doesn't necessarily have any impact on the fun-factor of a video game. Too many games nowadays concentrate on creating the most realistic experience possible, so they create an AI that can do everything from wage international warfare to prepare a can of bean soup. But they completely drop the ball on what makes games really
fun.
The funny thing is, people complain and complain and complain about how shooters nowadays are all the same, there are no differences between them, and how they are so 1337 because they only have one shooter called Modern Warfare 2 which is, in their words, a "mildly decent" (read: they love it) shooter. And then they complain about stupid things like AI and balance and how many sniper rifles the game has. -.-
If you haven't noticed already, I really don't like modern shooters and I also really don't like the people who've made them what they are. The ONLY first person shooter that I really enjoy is Doom (the original). Why? Isn't it the absolute pinnacle of everything I hate about FPSs? No!
Just read
this article to understand why. Go on.
Read it to completion, right now. It does an absolutely wonderful job of explaining just
why the original Doom has stood the test of time for almost 20 years, an eternity in the life of video games, and still has a very active and very productive community that is keeping it very much alive. The graphics aren't great any more; some might call them atrocious. But the game is still very, very fun, and this article does an excellent job explaining just why that is.
When you're done, I hope you do yourself a very big favor and get Doom 1/2, some of the more highly respectable modifications (believe me, there are some GOOD ones out there), a source port, and maybe a friend or two and have some real fun. What have you got to lose? If you don't like it, you can get a different game, and if you
do like it, like I have for the last 12 years, then you'll have a source of endless fun for literally years to come.
(I see you still haven't read that article.
READ IT.)
(Also Majora's Mask.)