If you think that a software engineering team can program a computer to do what Sullenberger did then you are deluded.
Actually just to repeat what Sully did is not a problem at all for programming. Accurate 3D landscape stored in onboard memory, several pre-loaded scenarios to look for and application of aircraft performance (incl degraded etc) to that scenarios will give you much more safe and accurate plan to be executed. This is not a fantasy, this is 10-15 years old processing capabilities which do not require a cryogen cooled 100 tons installation.
It is a matter of how many other potential "out of the box" scenarios are yet unknown and therefore cannot be programmed at the current stage of AI development. Just recently discussed this subject with the people who are involved in some prototyping
Watch this space...