at MINIMUM intelligent enemies should run to your last known location, move their cone of vision, and check it out forcing rolls
I hope this is what we will see eventually as the AI gets better and better.
That hide as a bonus action is unbalanced, I agree with. I think it should be a bonus action for rogues, though. A lot of things that make the rogue unique have been taken away already, and I think this would at least somewhat balance it out again.
