I think the limitations on super weapons are not needed as it will severely nerf the advantage of TEC Loyalist.
Instead, i think a nerf on the Novalith's damage is needed where it should not destroy an unprotected asteroid in one shot. Or put a hard cap that you cannot destroy a planet's occupation regardless how many Novalith you used on a planet, such as leaving a bombarded planet with 5% of the health remaining to put a penalty on the taxes gained by the owner. Or throw in a slight effect to slow down the growth of the population after bombardment to regain the planetary tax rate to normal. This will not completely decimate the opponent's economy where a late game player should have an extensive trade network to support their economy. In addition, this also serve as a warning to the receiver that they need more Trade Ports to sustain their economy with low planet tax.
In my opinion, this fits the lore of the TEC where they are trying to ruin your economy to destroy you. This is also to encourage the TEC Loyalist to destroy the planet with their own fleet, than sitting in the base and destroy enemies planets with no offensive fleet. It is unfair and not fun to counter as the opponent with Novalith in its current state.
Both Advent and Vasari super weapons are sort of support weapon on the fleet. Why cant Novalith behave the same? It should not be an offensive weapon to begin with, where it can be used as a complement to an offensive force, such as allow a planet to be destroyed faster by removing 95% of it's health almost instantly. On the other hand, serve as a harassment weapon, to deteriorate a Terran planet's population growth.
Hard cap is just a terrible way to solve this problem. A careful redesign of the superweapon will make it more fun for the user and the receiver. There are definitely other ways to redesign Novalith, such as the Supreme Commander method of controlling superweapon by asking the user to pay for each warhead. I do not think that this is a good option for Sins of Solar Empire.
I sincerely hope Iron Clad will retract the idea of putting hard caps on super weapons.