There is only one, really big problem:

Problems cannot be solved with the same mindset that created them.
The biggest problems with AI is that they are stuck.
They cannot change their mindset.

And another problem, i guess there are two:

People really do not know what they want. So that really cannot be put into an AI.
The universe is a "what if" construct.
And you are supposed to run out and find out, what if...
What if there was chocolate and vanilla ice cream? Which do you like best?
What if there were more flavors of ice cream?

And the biggest problem of getting to where X=Y, that makes three... and counting:

The core values of people are often not mutual. And often mutually exclusive.

We should have three political parties in America (but the elite couldn't have that.)

Group A: wants structure
Group B: wants safety
Group C: wants freedom

And carried out to any extreme (sometimes just taking the first logical step) anything that satisfies one group, scares the hell out of the other two groups.