Refraction on an average day, and gravitational lensing (if the earth were massive enough to cause a significant amount of it), cause light to bend back towards the surface of the earth. If the earth were truly flat, this would create the appearance of living in a bowl. Also, there would be no clearly defined horizon; things would simply fade as distance increased.
'Bendy light', as required by all FEH's, demands that light always bend away from the surface of the earth at a rate of ~1° per 111km. This would only account for the appearance of a horizon, and 'sinking' objects though. To account for the sun appearing where it does would require light to bend in a very convoluted manner, and not just away from the surface, but horizontally (left and right) as well.