TL;DR - UI functionality should be in a separate gem to solve many problems

Basically to decouple the functionality from Guard, because it's a maintenance nightmare:

• reliance on global state
• dependency on other Guard:: modules (even though it's just for outputting in color)
• mixing up logging with screen output
• hard to refactor without breaking compatibility
• hard to test because of global state / singleton
• color handling is not transparent
• too many responsibilities in one class (logging, option handling, coloring, line reset, deprecations, screen clearing, scope name, backtrace filtering, requiring win32console) while none are actually Guard-specific
• options exposed as a hash makes little sense (logger options during init) and just makes the interface confusing