The latest hotfix (3840) has a fix for shield assist repairing full HP when stalling resources. Now stalling resources also reduces the shield repair amount, which means that T3 artillery will kill bases if you don't have enough resources to assist against it.
If necessary, we want to implement a balance hotfix for shield assist costs. We can adjust mass/energy consumption and buildpower effectiveness (m/s/bp, e/s/bp, and hp/s/bp).
The best evidence for making changes would be replays, since the path to a T3 arty lategame is complex, so please provide them here. Opinions are also welcome but are less convincing so they need wider agreement.
For adaptations to the new patch, I encourage trying to build multiple shields, since recharging shields is much more efficient than assisting, and if you still assist for reliability, repairing 15% spillover is also much cheaper.
An example of a very convincing replay would be a relatively even game up until an arty vs land/air/navy attack, with the arty dealing far too much damage, despite good shielding technique (lots of buildpower, multiple shields), and proving that arty is too good of a "next step" in an even lategame compared to attacking with lategame units (which normally should be providing the reclaim requirement to afford arty).