Currently the t2 artillery is not used at all, that has 2 main reasons imo:
1. They are really expensive, mass costs go from 1680 for cybran to 2079 for aeon.
2. You really need a plenty of them to let them work reliable.
I would suggest a complete balance rework, lower costs and more reliability. I would also bring in more faction diversity, for example:
sera: high rate of fire, low damage, low splash
cybran: generally weaker than the others, but stuns
uef: the good old default artillery
aeon: low rate of fire, high damage, high splash
The main goals of a t2 arty should be to defend you against t2 naval and maybe mmls.