What do you think extra megapixels would give you?
Judging about quality of the camera by pixels count is silly.
Using a well-corrected lens of an appropriately longer focal length, and thus a narrower field of view, with or without panoramic stitching, will provide at least[1] the same linear resolution of a given subject, but with less sampling error.
[1] At least, since apochromatic correction is easier in longer focal length lenses provided that no super-wide-aperture bokeh heroics have gone into the design. Rectiliearity (the absence of barrel or pincushion distortion) is also easier to achieve. Flare can be reduced without inducing undue mechanical vignetting, increasing contrast.