In my opinion Baragon should have been allowed to keep a variation of his heat ray for GMK, granted, he was obviously no match for Godzilla, but if he'd been able to employ hit and run tactics, i.e. take pot shots at Godzilla with his heat ray or spit fireballs or whatever then burrowing back underground to keep him guessing where he'd strike next, their battle would have been that much more entertaining.
They definitely should have kept the glowing horn as well, just makes him look that much cooler :3
And yeah, Masers are basically the mid way point between conventional weapons like tanks and & jets and super weapons like the Super X series or giant robots like MechaG or Moguera. Masers aren't always effective against giant monsters, but they're better than normal firepower, especially against lesser kaiju like the Gargantuas.