Manually keeping autoloader class names up to date time consuming and unnecessary burden. Additionally it bloats extensions.json which can get thousands of lines long. Replacing the autoloader section with simple PSR-4 declaration makes it shorter.
Translate is mostly split into directories with some misc files here and there that need special consideration, so this should be relatively straighforward.
Slightly more complicated is to not break other code using Translate's classes, mainly TranslateSVG and CentralNotice come to my mind.