Personally I like the heavy weapons squads just because of the concentration of heavy firepower they provide as opposed to wasting lasgun shots by including all of those in infantry squads (also during the progress of buying so many steel legion infantry squads I have inadvertently acquired a ton of missile launchers

)
But I do see your point in other heavy weapons teams perhaps being more suited.
Would it be worth it dropping the Master and ordinance and instead finding a way of putting in a priest with an eviscerator to go with one of the infantry squads (also would drop one of the plasmas and replace with an additional flamer)?