I'm finding that a huge challenge with collaborating with clients in the CMS and E-commerce systems, is that they don't have a concept of what damage extra invisible characters do to a layout. So I can obsess all I want about the spacing after a rich text field, but they might leave three or four hard returns after their text that move the next item 60 pixels down the page.
As much as I try to be an educator, this is simply just something that non-designers never think about, so it would be good if the CMS and E-commerce did some of this automatically, or at least showed people what invisible characters were there. You could highlight in red any doubles, with a hover explanation of why they will throw off the design, nudging them into better behavior. Or you could simply not print the second of any of these characters to the page, which would be my preference.
The most important would be automatically disregarding any return characters at the end of a block of text. If you look at a CMS entry, these are almost impossible to see, and do the most damage to layouts, as they actually move elements outside of the text box. They are also probably the easiest to program an automated editor to remove.