AI in its' current state is at best still a very narrow self-learning system without self-conciousness. Based on technological progression, we can only assume that sometime in near-term future (let's say 20 - 40 years to be conservative), we will build a sufficiently complex system as to create a general AI, capable of handling multiple disciplines, ala human.
At that point, IMHO the question becomes - can the machine become self-aware. If we can truly create an artificial conciousness, then I'm not sure how you can NOT be alarmed. Evolution is way too slow to keep up with technological advancement, and at some point, someone, somewhere, will give it too much control. I don't care how careful we are at designing moral code, because at some point, a self-aware AI will see how much smarter it is. It will look at us as we look at a dog, and at best we will become just another cog in the food chain, no longer the masters. At worst, Earth will be cleansed of the human parasite to restore the natural balance.
If self-awareness is actually "not a thing", then all bets are off.