The problem with your argument is that your standard melee fight is NOT a charge of two players across a room in a dramatic clash where they both stand samurai scene style passed each other waiting for one to drop dead. Most melee fights are the result of spontaneous and unexpected encounters, where two players meet each other unprepared and close enough to where guns aren't a quick enough kill. Or as a finish in a close quarters fight. Shoulder charge just ISNT feasible in these situations since it requires prepreparation, and can't be summoned up in the few moments you have to act/react in that situation. And the standard Titan melee loses in that scenario most of the time. Shoulder charge is definitely deadly, and incredibly potent used right, but this makes up the minority of typical melee situations.