I read through most of this thread but didn't see this idea. I was reading another post and it made me think about the shadow ability. I just thought of the Oak/DA combo... oak shields DA, he shadows rook out of his tower farm and boom... dead rook and shield saves the DA from the towers.
For balancing, I would propose that the shadow ability purges all effects on the DA (yes you could use this to your advantage to remove DoTs or tracker), but on the whole I think it would force you to think twice about the ability and stop you from buffing the crap out of yourself to basically remove all the potential drawbacks on this ability.
Otherwise I can see using a Health stacking, using a sigil and then shadow... or the shield/shadow combo described above and then the only drawback becomes mana use. I know that oak could still shiled after the shadow... but maybe you could even do a 'imune to effects for 1.5 seconds after shadow' type thing... basically shadow is a game changer for sure... and right now there doesn't seem to be much of a deterrent to using it...