Corellary petition to not have Nunu's rework have % damage reduction
This is the "true damage" of tank stats and is a form of invisible power that makes for really bad gameplay moments and balancing disasters.
When a champion has % damage reduction, it makes them able to tank full combos while building full or near full damage
has been an issue in his past versions due to his ult being a get-out-of-jail-free card in a full AP build only when his entire kit was reworked to be usable as a pure support was he in a balancable spot.
E combined with her hybrid AP/Health items lets her do full rotations while the only counterplay is to wait around hoping she doesn't kill you before E wares off, or to do a shitload of true damage, a plague on the game in its own right
and especially the constantly recurring abomination that is reworked
all fall into this same category of getting a free pass to do a metric tonne of damage with near impunity only becoming vulnerable when their % reduction finally wares off.
So please. Do not give Nunu a dash or % damage reduction in his rework. Give him a shield, keep his telegraphed sustain in some manner, let him inhibit enemy mobility instead of having to have his own, but please, please, don't continue the spiraling trend of mobility creep and power creep we've been seeing.