My neon: Instead of constantly and randomly shooting a wide circular area with weak pointless shells, Tremor would unleash a
creeping barrage in a line pattern with a salvo of powerful, large-aoe shells with significant smoothing.
Multiple tremors could then either focus one target to maximize point damage, or line-attack, effectively saturate the entire area, guaranteeing some amount of damage to every point.
This would make it at least able to hit targets directly, and would also make it quite fearsome to be hit by such a shell. Currently even a direct impact from a Tremor shell doesn't seem to kill even a flimsy Defender. This would also make it much more practical to smooth out tank paths before an assault. It would generally massively increase the wow factor.
The barrage would start somewhere from half tremor range and creep to full range. Ideally the barrage should end behind the target, but that would mean people would try to extend range by attacking at max range and have the barrage's extension clip targets. Ideally, the exact target point should be impacted only once; each spot on the barrage line should be impacted once.
Tremor should be immobilized while performing the salvo to avoid abuse and to make implementation simpler. Immobilization would make it more snipeable, amplifying its quantness, especially if the barrage takes a while to creep.
Upon completing a predetermined number of shots constituting the barrage, it would start the barrage anew. Reload time should be tuned to barrage duration, enabling continuously cycling barrages if Tremor is left to fire indefinitely.
A fearsome siege unit bringing slow but definite doom to anything too slow to escape the creeping barrage. Now you know why you fear artillery.