Generally, I am in support of an remap of the nuke system;
As CN grows, in general it becomes harder for newer nations to move into the top 5%. Its a sort of an issue with starting point; you cannot hope that a 0 day nation will catch up to a 750 day one (but the 0 day nation should not catch up anyways). The argument that you could get into the 5% is very valid, but we should give newer nations a easier path to nuclear weapons. (Clearly, I am not advocating giving more than 5% of the CN population a chance to buy nuke)
However, I believe CN needs to adapt the LW system of nuke buying, where a very high infra and/or tech barrier [on the magnitude of 6500 infra and 1500 tech or 2000 tech] (fixed, instead of the ever increasing NS) should be used. A fixed rate of growth is incompatible with the ever increasing nuke barrier. However this system can run into major problems in the future as average NS in the game rises dramatically.
Fun fact: average NS has doubled since GW II (for sanctioned alliances), despite numerous wars, and two NS nerfs. (Heh, this NS nerf is mild compared to the last one, it caused like 400 nations to have 49-51k NS.