Crack flesh - Don't see any reason you would use this at later level as a transmuter. I categorize this (like with many invoker powers) as a 'beginners' spell that you throw in as a means of explaining how you learned harder spells later on down the road. Maybe someone will have a reason I don't know about (and will be glad to hear) as to why you would use this in combat once you have mental jolt much less the various disruptions.

Toughened skin is another good example from transmuter class - its basically useless as a svirf as you can inh stoneskin and useless as a transmuter once you can use corporeal hardening.

Sheen of stone (invokers) becomes pretty much useless once you can fairly easily get stoneskin.