GS + Sword/Warhorn ?
Fast Hands and Forceful Greatsword come to mind.
While that may be fine and dandy for WvW roaming, for leveling (assumed open world PvE) Forceful Greatsword may be more beneficial with the reduction on GS cooldows adding additional mobility.
IMO, Greatsword really isn’t worth using without Forceful Greatsword and/or Slashing Power. The might stacking boon on crit/cooldown reduction of Forceful GS is what puts the DPS of GS anywhere near other weapons (when traited).
(edited by Artaz.3819)