I don't think that's the issue. I think it more likely that Madison et al. would have feared that, without such language, the RKBA might be interpreted as only applying to a small subset of weapons, excluding some that would be necessary for effective military use.
You may be right, but don't forget one thing: it wasn't Lefty radicals like Hussein who first started placing "common sense" restrictions on the right to keep and bear. No, the first anti-gunners were "law and order" City Fathers (i.e the rich and famous), local police agencies and "right-wing" judges - all representing the interests of the wealthy- who feared what Old West desperados, Sacco and Vanzetti-type Anarchists and (later still) the Bolsheviks and Prohibition-era gangsters would do if they had ready access to firearms. I think that the Masters of the Plantation and the Captains of Commerce and Industry would have been much less apprehensive about militarily effective arms in the hands of an organized Militia than they would have been about a coach gun or a pocket pistol in the hands of a slave or an angry underling.
What do you mean "right-wing" judges? The terms have shifted meaning over the years. When power was dominated by private monied interests, authoritarians favored letting them keep their money while those seeking to tear down the existing power structure sought redistribution. Since redistributionists have gained power, now they want to bolster the government power structure and reinforce their positions.
In neither case would I expect the founders have been too pleased with authoritarian attempts at disarmament.
The first gun laws were intensely racist in nature. They were designed primarily to keep firearms out of the hands of newly freed Negroes.