To increase a tank's surviability in warzones, without making massive wide scale changes to how the game works, I suggest this:

 

Deep in the tank tree, at next to final tree, tie in armor penetration reduction. Let it say something like this:

 

"In addition, all armor penetration effects are only 20/40/60% less effective against you."

 

As the game is now, armor penetration, or circumvention has run rampant (more so in my mind then the stun tactics). Tanks suffer the same damage from the same attacks in heavy armor as mediums do, simply because of high armor penetration. By giving the armor pen back, internal and elemental damage are still dangerous to tanks, but kinetic and energy (Railshot and smash are at the top of the list) will not be as dangerous to a tank. This change will add a modest amount of relief to tanks that are ailing in warzones right now.

Edited January 22, 2013 by Azrienov

The would help us on only against a few abilities though. There are far more issues with force/internal/elemental powers out there that outright bypass all of our defenses. Edited January 22, 2013 by vactus

I agree tanks have a number of issues to resolve, but I'm only suggesting a single step. I'd rather get incrementally better every patch than have a huge buff that everyone feels is completely and suddenly unbalancing the game.

 

As for internal and elemental, neither of these hurt nearly as much as a kinetic attack with high armor pen. Internal and elemental should hurt, and should exist as a danger to tanks who do not account for the threat they pose. That said, I still don't like force attacks that completely ignore shields.