Some datastores know about the Query hint Hints.JTS_COORDINATE_SEQUENCE_FACTORY and can use a lighter weight coordinate sequence.
Problem is the current GML2 and GML3 do not currently use CoordinateSequence but coordinate[], so they need to be switched to CoordinateSequence for the hint to make any good.
all output formats improved:
GML3, GML2, SHAPE-ZIP, GeoJSON