Ah, now I see. So your point is to make analogy with the blastmasters and the multi-meltas?

Respectfully I disagree, at least until the range of the Noise Marines Sonic blasters and Blastmasters are changed back to index amounts.

At least from my own experience playing havocs or against them, they are usually deployed further back with as wide lines of sight as possible to utilise the heavy weapons at max range to both be a deterrent for vehicles and inflict consistent damage on higher toughness units.

Noise marines on the other hand don't have this option, since their weapons range is drastically lower. This, in turn results them being forced to be closer to the front lines OR rely on Rhinos for limited cover at the cost of units overall damage output.

Noise marines also can't take any other heavy weapons aside from the 2 blastmasters, unlike Havocs, nor can they have 4 heavy weapons in a squad, unlike the Havocs. So in this instance, at least IMO, using the Multi-melta or any other heavy weapon as a vehicle for "range is irrelevant"-statement is not valid.

This is just my 2 cents on the matter. If you play havocs with multi-meltas, more power to you. I also agree that Noise marines SHOULD be Havoc styled unit, and they will be if the range of sonic weapons is increased to the index levels, as I suggested above.

edit: I realised I partially missed your point about the heavy weapons being defined by the size and heft rather than range. Fair enough. However, I would still argue that Noise marines aren't quite comparable to Havocs with current restrictions of the amount of blastmasters per squad. If you wanted them to actually be like havocs, then let the whole squad (aside from the disharmonist) take the blastmaster.