So, I just realized, we can have our first use of 7 dice come wave 4. E wing + R2-F2 + Stealth + R3 + obstruction yields 7 defensive dice. And that's without even knowing what wingman or decoy does.
I know that we can get to 6 attack dice already (Jan + APT, Jan + Exp + R1) and soon we'll be able to get to 6 via Jan + Opportunist + R1, and wave 4 will have the Phantom + R1 + Opportunist, but I don't see any way to exceed that, unless Wingman gives the leader an extra attack. Since the EPT is already spent on Opportunist, there would have to be a systems upgrade or something to boost the attack dice up to 7.
It wasn't too long ago that 4 attack and 5 defense was the most you could achieve. (Wave 2 upped the A to 5 and the D to 6 via Expose + Stealth, Wave 3 upped the A to 6 via Jan and APT or Jan + Exp + R1)... I suppose the game is slowly getting a power creep, since we all seem to agree (as does the math, from .31 dmg at 1v1 to 1.11 dmg at 6v6) that more dice favor the attacker.