I guess the 3th job skills could deal much more damage in KGC/BrGC...
For dungeons:
In TW the only useful 3th Job skill is the little devil summon
which can reduce DP and AP for around 30-40%
and the remained curse which can deal "continuous damage" to monsters is just a crab .... -1HP per second...
However those skills are pretty good for PVP
The trailers in Utube may not reflect the reality ( in dungeons) @@
I can post the details/translations if anyone is interested