You can absolutely, as a Rune-Keeper reach 200% Tactical Damage cap, 70% healing cap and 25% critical hit chance cap for all builds while also making the 40% light armor mitigations cap. You won't hit the cap on devastating chance of 10% or crit magnitude of 100%. I push devastate to around 8% and magnitude to around 50% I believe.

EDIT: Tactical Cap goes to 205% or 210% when in fire build, healing goes to 90% in healing build and crit chance caps at 30% when it lightning.