Do you have a uv filter on your lens? It will remove some of the haze which might make the photo appear out of focus.
Great shots. I always use multi segment metering when taking landscapes. Try it and see if it makes a difference.
I see some UV haze in #1. A UV filter or Polarizer would help. Editing per renomike's example is indicated too. If you aren't photo editing, you're working with half a system. Your 50D has adjustments to increase sharpening and contrast for landscapes. Give that a shot for better out-of-the-box results.
I took some shots this weekend at the beach and harbor. One camera has a ND filter and the haze killed the shots. My other camera has a UV filter and the photos appear sharper. Seill needed editig to balance the color.
You photos are not all that bad.
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