I usually try to get a window seat on the south side of the plane flying into and out of ZRH for the same reason, and in my experience it really does seem to come down to surface wind direction, as the side with the better view seems to be unpredictable. I generally pick a right side window for arrivals from the US, for a chance of a longer-range view even if the left side gets the better view just before landing. Cloud cover, haze, and sun position also do affect the view.

Even better than ZRH-GVA would be ZRH-MXP, but I take it you're considering flights to/from the US.

I've seen Mt. Blanc and the Matterhorn, but in my opinion the Lauterbrunnen valley just south of Interlaken is significantly more beautiful, especially if you visit (or stay in) either Wengen or Muerren (that's Murren with an umlaut over the u). The area surrounding the Sustenpass would come in second in my book.