This will probably be a very unpopular suggestion, but I think W2C should be nerfed a bit to give them a specific role. For example, JHP have an interesting niche as soft-but-large target killers - Hunchback Mutants, for example - but W2C are a strict upgrade over regular bullets, only limited by how many you can make or buy.
I think if W2C lost 5-10% of their damage, possibly in exchange for another 5% or so penetration, their role as the anti-tin cans and robot munition would be a little clearer.