Would be great to be able to define custom path after export, specially for images. I want to have the real path on my site in order to have the images where i want, not a fixed path 'assets/img/...', i need to create this dummy directory only to containt the images.
Wouldn't it be easier to just leave them where they are? I mean, that's a hella lotta work to have to alter all the image paths (unless you're adding them in with the relative links of another location when you're adding them of course, which doesn't make for good page testing). I too had this issue a lot when I first started using the program, but to be honest, I've found it a much more cleaner way to do things to just leave the structure alone. I reference things that are outside of it when needed, but it's actually a pretty good setup.
Having said that, there has been talk about giving us the ability to set our file locations on export, but I don't recall if it will be for all files or just certain ones. Try a search in this particular forum (ideas) and you'll most likely come across the conversations.
I use Notepad++ for post export changes. We generally have 2 image locations so I code my project to mimic that and then after export I load up all the pages and search/replace to remove assets/img from the code so the paths come out correct.