I think the shots look fine! It just looks like you're dealing with some harsh lighting and haze. A CPL may be useful for some of the building shots, in order to improve saturation and contrast and cut back on haze. The shots in the shade with the horse and cars look better to me. You should try to shoot earlier in the morning or find that golden hour later in the day.
The 5DIII isn't going to be that much sharper than the 5DII.
I would think the main reason to upgrade to the 5DIII would be for; more accurate and faster Auto focus, faster frames per second and improved higher ISO.
Hey Rich! Thanks so much for posting feedback, I really appreciate that you and the other posters took the time to give thoughtful responses.
Definitely know what you mean regarding harsh lighting and haze - these are definitely not my best photos lol.
I didn't expect the 5D3 pictures to come out much sharper/have more detail when zoomed in than my 5D2, I just was surprised by what I felt was inferior detail when zooming in. I understand Noise Reduction at High ISOs could be the culprit behind some shots appearing a little 'soft' but I was surprised by low ISO shots looking more pixelated when zooming in than my 5D2 shots.
I definitely LOVE the better features of the 5D3 over the 5D2, I just want to make sure people think the shots don't come out looking too pixelated when zoomed in. I've read online some people say they ended up getting another copy of the 5D3 which was sharper - I'd prefer not to do that, which is why I really appreciate people giving their feedback...