Guys the OP had as Sigma 28-70 f/2.8 he was happy with, I don't think he "needs to get used to" a lens that's only 4mm wider???
Both shots look out of focus!
1st was 42mm - 1/320 - f/6.3 - ISO200
2nd was 24mm - 1/200 - f/7.1 - ISO200
So its clearly not a "getting used to" narrow DOF situation, its clearly not a case of it being poor at one end and good at the other. In this case "the brick" looks like a bit of a paperweight.
As you have tried it in the real world, and it looks like the focus is off I would suggest......
1. Pick the focus point instead of using them all. I'm guessing if you shooting in P its possible that you have all focus points left on.
2. Don't focus recompose, as that will induce focus errors
3. If shooting moving targets or you tend to sway back and forth when shooting, try put the camera on AI-servo focus mode instead of one-shot.
4. Do a quick battery test in good light to see do you have any focus errors with the lens. If you look around these forums, you will find many cases of "the Brick" (aka 24-70 L) needing 1 or 2 trips to canon servicing to go from paperweight to brick status 
Once its working at its best you should be pretty happy with it.