I can't see how having to evade a circle rather than a sector is OP.
Yes, and the counterplay to the Tactical Support Regiment arty is to evade it until it stops.
1- Sector abilities tends to either be focus around the flag position or through the sector zone. In either case, the area of effect is way smaller than AC (arty cover) and you are limited to a specific region.
Sector abilities tend to be stronger due to this in comparison to pinpoint abilities.
Circle area offmaps have either a way SMALLER AoE, are either weaker or have a strong RNG component on them.
2- The "current" OP part is either the AI capabilities, mostly cause it's GG for any support weapons which can't retreat or the range of the ability combined with it's duration.
Right now it does TOO MANY THINGS WELL in comparison to ALL OTHER OFFMAPS in the game.
-It doesn't have restrictions to zone casting in comparison to it's power level (Sector arty, Assault arty, Close the pocket)
-Arrival/Landing/Ramping is too fast (Air superiority, Sector assault, Zeroing, Scavenge arty)
-It's both AI and AT
-It can't be denied in comparison to planes.
-Duration and range (AoE)
-It's pinpoint accurate
Instead of nerfing it to be equal as other offmaps, i think that limiting it's access/casting is better, specially if this helps the other ability (FoP) to be more useable.
So would the Arty cover damage the command vehicle?
Why would it? It only "tracks" enemy vehicles. I'm not saying that the center of the ability should cast on top of the command vehicle btw, just that instead of free will casting on any part of the map, you must do it from a nearby casting unit/building.