とりあえずこんな感じ？（先頭はdir順）
if "%1" neq "" pushd "%~1"
for /d %%i in (*) do call :sub "%%~i"
popd
goto :eof

:sub
for /f "tokens=*" %%j in ('dir /b /on %1') do (
call :rename %1 "%%~j"
goto :eof
)
goto :eof

:rename
ren %1 %2
if errorlevel 0 call :rename-retry %1 %2
goto :eof

:rename-retry
rem ---todo---
goto :eof