One T3 Artillery is more than 40 Percivals, even taking into account the cost of Factories. Even in a weaker form, that will still be enough to crush 90% of defences without issue. Currently, short of a stack of Experimentals being involved, there is no defensive fortification which can stand up to 40 Percivals and come out without significant losses.
Also, TML, Artillery, and Nukes are not capable of fending off the (Hopefully) increased number of T2 land units.
The only worry I have is the Experimentals becoming the new T3 default (Again). I've already mentioned making them far more expensive and epic ala Vanilla, and Zock I think is kind of on board, but it's out of the scope of this patch unless the T3 nerf consequences are far more severe than we are anticipating.