One the one hand I can understand the issue that one person wielding mod power in many subs is a problem, especially if that mod is prone to abuse of the mod position.

On the other hand, some subs, especially smaller ones, might go modless.

What I would have done differently is that I would not align this rule on the number of subs alone. The size of a sub should also be a factor, as well as overall number of mods in those groups. A good solution would be not as easy as what they propose.