For starters, for players who still possess standard 1080p HDTVs, we're able to offer far better image quality. We've got a number of techniques at our disposal. The most logical one is supersampling. This is a very high-quality anti-aliasing technique, which basically means we internally render at a higher resolution (close to 4K) before shrinking it down to the final 1080p resolution. As our internal calculations are done at a resolution much higher than 1080p, more detail survives before we shrink it down to 1080p, resulting in smoother edges — virtually no jaggies — and a more stable image.
We're also looking at enhancing the quality of our shadow maps and increasing the quality of our anisotropic filtering. This is a technique which increases the quality of texture sampling, resulting in more detailed environment textures. We still have to tweak these elements of the 1080p output quality for the final game, but we have quite a bit of power yet to play with.