Since the merge and even event sales numerous preimium/event squads at various BRs dont really compete with researchable squads, mostly due to lack of specialist as well as smaller typical size (excluding Paras).
The current Christmas event with 5 squad assaulters highlights this issue, as while helpful for players grinding into BR5, theyre typically useless for already established players.
I think a simple elegant solution would be to offer small silver income bonuses to the rarer seen event/premium squads. This can be 5-20% depending on the economy and apply to non para/flamer teams in order to encourage players to sacrifice raw min/maxed combat power for more income gains in battle.
Just thought it would be a simple elegant solution to the issue of these squads becoming obsolescent.