We don’t need a fancy new AI. The old one fits its purpose just right. (Shoot them, kill them, loot them, profit). IMO we need more diversity. More different missions, sites, etc.
Why can’t NullSec sites be modular. Just let every site have one or two acceleration-gates, so that afk players cant farm them indefinitely without getting to the next stage. Also every stage should be random, for example. First stage has 2 normal waves, the next one could be similar to a DED pocket / have scramblers and so on. That wouldn’t be so hard to implement i think. One core mechanic for putting them together and then insert a pool with some parts of already existing sites. Done.
This could also work with missions. The goal of every mission could stay the same, but there should be a chance to “get off track”. Like an appearing problem, where you have to clear another spawn/pocket, collect some things to disarm sentrys, maneuver through a minefield or whatever to get “back on track”. This should be a option for getting extra ISK of course 
PvE should be fun to do, and not something where you need a bot, or be afk to stay awake.
PvE is the essential step of getting into PvP. It’s also necessary to obtain money, to finance it. When you loose a ship, you shouldn’t be frustrated because you have to grind twenty missions/sites which are all the same/kind of similar to get it back. Thats no fun, that sucks, but now it’s just like that, and thats the problem.
If PvE would make as much fun as PvP does, I’m sure a lot more people would play/stay playing EvE.
There is one thing missing, and thats unpredictability. As soon as you can look every site up on the internet to see how it works, it’s no challenge anymore and then it starts to get boring.
TL;DR:
More diversity in missions / anomalies (whether Null/WH/High/LowSec)
Maybe a modular mission/site-system
Get rid of predictability in PvE
Thats just my two ISK 
Thanks for reading my wall of text (or the TL;DR)
-Space