The short answer to this question is yes. Most Android data recovery software that claims to find data on unrooted phones is able to find hidden data and thumbnails but is ineffective at finding or restoring truly deleted or heavily damaged files without rooting the device.
On this list, the only exception to that rule is TenorShare UltData. While this software can recover some file types from some locations without root, it seems that advanced rooting is still required in certain scenarios.