I have a C330 and I've always lusted after a Pentax 6x7.
The C330 works fine as a landscape camera. For me, it is at home on a tripod rather than used handheld. That makes it slow to use which is good for a contemplative landscape. It's adaptable to eyelevel or waistlevel viewing and has good interchangeable lenses. It doesn't have any superwide or superlong lenses, however. The 55mm is not as wide as a 28mm on a 35mm camera and the 250mm lens takes a lot of the bellows which limits close focusing with that lens. Despite these drawbacks, it works well if what you want is improved negative quality.
The Pentax 6x7 has several advantages. The negative size being the primary one. I seem to crop my 6x6 negatives most of the time to fit 8x10 and 11x14 paper dimensions. This gives the 6x7 even more of an advantage. The Pentax system includes longer and wider lenses with accessories like a 35mm camera system. While it can be used with a waist level finder, shooting verticals would not be as easy as with the prism finder. The Pentax lenses are reportedly outstanding.
As I said, I have wanted a Pentax 6x7 for years, especially for landscape/scenic/nature type photography. I've never been able to afford one. However, I recently bought a Pentax 645 with 45/75/150 lenses. I've been very happy with this equipment as a better handling alternative to the C330 (which I plan to keep). The lenses are excellent--the 75mm being outstanding. Since I crop the 6x6 negative most of the time, I've given up nothing in print quality. It's another option for you to think about.