You just need 38 states to agree to amend the Constitution and repeal the 2nd amendment.
So low population state "strong-arming" the majority is OK? The design is poor, it is Tyranny by the minority.
The design appears to be working well looking over the 240 years since the US' Constitution was ratified. A broad consensus of the states, _not of the people in the US as a whole_, is required to effect large scale, national changes.
The intent is to make it changeable, but not too changeable. The constitution is the supreme law of the land, and it's not beneficial if it can be changed at a whim.