Well, stitching together real-world imagery can be really effective. Take a look at Guild member a2area's work.
Your patchwork seems to be placed at different illumination angles, though. I can easily imagine earthly mosaics needing to incorporate material taken from wildly different seasons and times of day, but as a map your plausibility will be enhanced by no distracting differences. You're right that the coastline treatment needs work - the vagueness doesn't work.
Those two SE lobes have odd rivers, for the terrain indicated.