Not everything have to be combo-ed every single time. Sh*t is situational, Thundaga is fine for rushing kills or when you have Parsimony up, it just not reccomended for a long drawn out fight.
THMs that only knows how to nuke (when THM has so many enfeebles) is as bad as DPSs classes that only knows how to WS and doesn't know how to take care of themselves.