If you take a look at the videos posted of my SW beating the Tartarus bosses, that should prove SW can beat Hard Solo Mode. Hardest boss, at least for me is the last one because of the mobs.
Precision no longer has the base atk and ch-atk boosts in response to reductions of ME's Crit-Void in her buffs.
Defense is among the smallest factors in Damage Reduction that mainly would show itself in the form of longer skill rotations. If the effectiveness of the defense debuff needs to go up, so be it. It won't make much difference in the big picture.