UE4 is a complex beast that will take a long time to master. It takes a team of specialists to truly leverage its power. UE4's market is high-end PC and console titles. UE4 is pretty.
Unity targets small shops and indie devs. It has quick iteration times for rapid prototyping of gameplay mechanics. It takes more work to make things pretty in Unity.
It will be easier for Unity to ramp-up its visual fidelity than it will be for UE4 to revamp fundamental workflow. We're already beginning to see these changes, like new GI (global illumination) system and physically-based materials in Unity 5. Perhaps Unity v6 or v7 will have graphics on par with UE4.
Although you seem to know what you're talking about, my experience isn't that clear cut.
I've used UE4 quite a bit. Just using blueprints, I didn't feel like I needed to be a specialist to do really cool stuff. And I wish it had something like C#. Also, it wasn't that quick to get something looking great in UE4 and took quite a bit of practicing.
Unity targets small shops and indie devs. It has quick iteration times for rapid prototyping of gameplay mechanics. It takes more work to make things pretty in Unity.
It will be easier for Unity to ramp-up its visual fidelity than it will be for UE4 to revamp fundamental workflow. We're already beginning to see these changes, like new GI (global illumination) system and physically-based materials in Unity 5. Perhaps Unity v6 or v7 will have graphics on par with UE4.