I actually wish this were the case. Realistically, Superman should have some degree of enhanced strength and speed even when in a depowered state since Krypton has a higher gravity that Earth. But every single writer never takes this into consideration and Superman is as normal as any other human whenever he loses his powers.
He should always have a baseline that would still be somewhat powerful, and retain his supersenses...
Or Maybe keep much of his invulnerable, as His body is channeling his residualk energies towards that still?