I've been doing a lot of playing around with the CMS and I think that it's a great product that just needs some upgrading.
 
I would start with the fact that ALL items should be editable via the CMS, including header and footer. For the footer to be editable via the global settings seems out of place, and not to be able to include blocks seems a little odd as well.
 
I do like how we can easily move blocks around on the page, however I find it odd that we cannot stretch blocks to cover all 3 columns, or to even add an additional colum if necessary.
 
I think we should be able to add as many rows and columns as we desire, should be able to stretch rows to cover as many columns as necessary, etc.

Stretching rows across two or three columns would be great.
 
And if that was possible I would agree that more columns may also be useful.

I agree that the CMS could be a bit better with more control over the custom layout aspect