Another option to throw out there (instead of improving t2 as a counter to guncoms) - increase the range of Aeon gun even further (say +2 or +3 above what it is now), and increase the dps from ROF to x2.5 or x3 instead of x2, but increase the cost and build time of each upgrade to be that of other faction’s combined gun upgrade.
That way you make it much harder for Aeon to get both upgrades vs other faction’s guncoms/much more of a risk to doing this (and more counterplay options), but still keep things different and provide more meaningful choice for the Aeon player when upgrading.
Meanwhile t2 pd as a counter would still be almost as powerful against a double upgraded acu but no longer have such an investment disparity (so becomes relatively better). Non aeon guncoms would have a clear window to push forwards while the aeon acu is upgrading; range only aeon acu + army is weaker than non aeon guncom + army at the t1 stage, etc
It’s much more interesting to have factional variance that provides tradeoffs and is relatively well balanced than just changing it to mirror other factions range