Mal

A larger sensor basically just gets you more detail and more light. Extra detail is usually translated into extra mega pixels, which is useful for landscape photography or for large prints. Generally landscapes are done at a narrow aperture (f8-f11) so extra light can be useful if you're doing late evening/night landscape photography.

Autofocus does a really good job of getting sharp focus really quickly, so it's more accurate and significantly quicker than focusing manually. Zoom is always operated manually with the lens ring, and manual focusing can be done as well if you want. Some lenses have set focus gearing and an auto/manual switch, but some have gearing set up so you can use auto focus and then manually adjust the focus with no need for a switch.