I guess that you need to know what you are dissatisfied with regarding Canon and Nikon images. There is no difference between formats. A larger format is simply larger. Now, there are advantages with size.
A sensor is an electronic device, by and large, it just captures photons. There is no magic in sensors. Color is not created by the sensor it self but by the color grid array in the front of the sensor and the software processing the raw image. It is well possible that some CGAs (Color Grid Arrays) are optimized for better color separation (like Velvia) and some others may be optimized for better high ISO performance.
The colors we see are created by the software and they are always tweaked, except when scene referred rendering is used. The tweaking depends on software. Some software may have better profiles for the camera.
So color is CGA and software (with format not at all involved).
Noise which is related to smoothness and DR depends mostly on the number of photons captured. A larger format will collect more photons, if exposure is the same. The darkest parts of the image will be affected by readout noise (from the electronics) this is an area where MF is not very good but recent sensors from Sony, Nikon, Pentax and others excel.
Resolution is mostly depending on sensor. More pixels, better resolution. Fine detail contrast depends much on lens and AA-filtering. A larger format will show any detail larger on the sensor, that is good for fine detail contrast. Stopping down excessively causes diffraction, with larger formats you need to stop down more for DoF, so diffraction may affect fine detail contrast more.
Another important factor is focusing accuracy. Modern DSLRs have live view, where you can see the actual image on the sensor. If live view is enlarged so you see each pixel you can focus exactly, but your focus can still be spoiled by focus shift.
With MF it may be difficult to achieve optimal focus. Alpa allows the back to be shimmed within 0.01 mm, and has extremely long calibrated focusing gear. You can use it with a laser rangefinder to focus exactly.
I'd suggest that the article below is recommended reading:http://www.josephholmes.com/news-medformatprecision.html
But issues do exist with all formats.
The most important factor is the photographer making the best of his/her equipment. The equipment you know you can rely on is the one that best for you.
I've spent probably 50 hours this week on LL, reading so many different opinions that my head is spinning. I'm tired on the mediocre quality images that come from Canon vs Nikon, and 35mm in general; just seems like something is missing. Medium format just seems to envelop the viewer in the photograph. So what is the best setup for landscape photography? Is it a 645 w/ a Phase One back? Is it a Blad H4D, Leica S2? What the heck is that Alpha TC looking contraption?
Besides the atmospheric aspect of medium format photography, I need a system that has the least distortion, the most sharpness, and usable in the outdoor environment. Now before someone jumps at me as say "the best camera is the one you have with you", I've gone down that route, and it's just not the right answer for me. The best camera, is the one that does what I need it to do; and that is capture the essence of my environment. I've saved my money wisely and have a maximum budget of $50K. Hope to get some sense out of all the information presented on LL, and ultimately reach photographic nirvana. Thanks in Advance!