The Caedus/Zannah squad is definitely a tank squad, which by definition doesn't need a lot of activations. The thing is, though: you'll get eaten up by solid shooters because it lacks shooters of its own.
As an example, Hinkbert and I both played Mace/GOWK at Gencon. However, whereas I beat Darph Nader's Soviet Trooper Swarm twice (the 2nd win was very convincing), Hinkbert lost convincingly to the same Trooper Swarm in the Quarterfinals...he even had a Shieldbearer. The single difference was that I had a shooter (Rex) who could make a difference, whereas Hinkbert had no shooting capability whatsoever. The Caedus/Zannah squad will face the same issue: tank squads without shooting capability face an uphill battle vs solid shooter squads...and the thing is, Hinkbert's squad had far better movement breakers (Foul, R2) than Caedus/Zannah do. So I agree that they will beat a melee squad almost every time, but I think you'll find real trouble vs other squads.
By contrast, the Mace/GOWK squad would eat the Caedus/Jaq squad alive, because once Jaq goes down (which will be quick vs a good player), it'll be Caedus vs the world...and he'll run out of hp and fp pretty quickly (remember that Mace can Absorb fprrs).
Tank squads are tricky: if the balance in squadbuilding isn't exactly right and/or if they're not played just-so, then they can fail to perform. So keep playtesting it and see how it does vs a variety of squads. I think it's cool that more tank-iness is part of the picture!