Buff Defense Up/Down

Coldth

Defense Down is so weak that it is possible to do less damage to a character after inflicting it, because the +/-5% variance is sometimes more significant than -50% defense.
Even for a max level, max stars, and fully geared out Old Ben, who has the highest armor in the game at 406 (~40% damage reduction), he would only go up to 609 armor (~50% damage reduction) from Defense Up. That's only an effective 17% damage reduction gained from Defense Up - compare that to +50% damage from Offense Up.
Several weak characters would be more viable by bringing Defense Up/Down in line with other status effects, such as Mob Enforcer, Luke Skywalker, Eeth Koth, Ugnaught, Jedi Knight Guardian, and Stormtrooper.
There are some who may need nerfs to re-balance, like Phasma, Wedge, Bariss, and Royal Guard.
If you ask me, I'd say doubling the effect of Defense Up/Down would balance it with other status effects. Defense Down stripping 100% armor would only give about +35% damage against most characters, which is still less of a difference than Offense Up.
Leader abilities that increase Defense also need to be universally buffed. As an example, Fives' damage reduction only goes from ~39% to ~43% from his maxed leader ability (+65 defense). Tripling it still wouldn't make it viable, but it'd be a start.