Not rated on this type, but for me, if there's a probe(s) heated on the ground, then there is the possibility of an air/ground sensing fault and this should be checked. I've had similar faults myself and have always investigated further (one was a failed relay, the other a faulty probe)
Having said that, the report does state that for every eventuality with the MEL written as it was then (not sure if it has since been amended), a defect in the TAWS would not have been detected by the maintenance crew as there was no requirement to check it.
However, the maintenance crew did make some mistakes the main one being that having pulled the probe heat CB they didn't cross refer to any MEL refs for RAT sensing (i.e the inoperability of the auto throttle system, which appears to have concerned the FO somewhat). The report specifically states that pulling the RAT probe heat would not affect normal operation of the TAWS in a correctly functioning a/c.
This terrible tragedy occured mainly because the flight crew missed several cues and had not correctly set their flaps/slats, the TAWS was inoperative for a reason undetermined by the investigation and the Spanair Ops manual diverged from the Boeing/Douglas recommended procedure and didn't call for a TAWS check prior to each flight.
The maintenance crew are in for a torrid time but any decent lawyer will throw the charges out of court.