On removing sleep and scathe... no.
BLM is not the powerhouse at low levels it is at higher levels, and you said it yourself, sleep is useful early on.
BLM is actually one of the more fun jobs to play early game because of this.
Why does it matter that a couple of minor skills become useless by end game? Just don't use them.

They could be enhanced with a trait I suppose, but there's no need to remove them or buff them to the point they're no longer low level skills.

Freeze definitely needs something doing to it though.