Defensive only currently has 2 T4s; that is part of the reason.
I run a defensive company, I like it. It's either artillery-based or support weapon based that is strong for defensive atm. If that's not your style then it's pretty meh too.
I keep seeing this around the forums, but I never ran support-heavy with my Defensive company. The reason I'm mystified at this is that Defensive only buffs paks and all units by 25%. Granted, the pak and health buffs are very powerful buffs, but there's nothing that buffs the mortar and mg (except for officer supervision, but that's like an all around buff). I think Terror has more support weapon buffs than that.