I have been working with Blimp and one problem I encounter on a regular basis is that it is difficult to understand what is going on behind-the-scenes as far as changes in Blimp layout files are concerned. The file format is a binary format that isn't readable except by the Blimp tool.
Working with the Git version control system, this makes the code difficult to manage. Only binary blob changes can be stored and it is not possible to see a diff from the previous version of the code to the current one and understand fully what has changed before committing. When opening the Blimp tool and opening a file, sometimes it will insist on saving "changes" even when no changes were made, even a simple open-close. The nature of the changes aren't disclosed, and I sometimes run into issues where upon changing one element, there is a side effect on another element of the same project. Text files make this easy to correct.
For binary assets (such as images), either a storage in separate files or embedded as a base-64 encoded element would be appropriate. Either would be excellent for version control. The binary format is a barrier to productivity with the Blimp tool and its respective video switch products.