At least it’s still legible, but I see your point. I think it would be a helpful addition to SketchUp, but also… The more feature you have, the more features you have to maintain (bug check, etc.), teach, etc. Even the select tool has caused lag on Windows computers, so I’m assuming keeping it simple would be easier for the developers to manage… and less buggy for the users.
My main problem with the dimensions is when they’re overlapping each other, rendering them illegible.
Although, it’s fixable by moving some dimensions around, but it definitely takes some time. Maybe I’m doing it wrong. I don’t know.
The white background wouldn’t solve that because it’d block out other dimensions, but it would help with clarity in other instances (like your example).