Seraphim and Aeon tech somewhat mirriors each other. It's like the Aeon had a rough idea of what seraphim technology did and had to fill in the gaps. You can see this in their experimentals (Large flying unit with powerful energy weapon, tall robot with orb head and other weapon systems), commander upgrades (RAS-ARAS, two gun upgrades, more HP through shield/Nano) and building design (Salvation and Hovatham).
That aside, if the gun splash were slightly more expensive than the standard seraphim gun upgrade, but had its damage lowered to closer match its cost, that sounds ideal to me. Of course, you'd have the problem of balancing the splash and total damage against units with paper armor like the aurora, but I think it would be a good start. More commander builds would open up, like how other factions forego the gun range upgrade and go for Tech2 for the additional HP.