I've run engines with bent crank noses and other than shorter than normal seal life, any vibration was not noticeable.

Something I left out on "the damper has spun due to failed rubber". Some engines are externally balanced. This is where the damper and / or flywheel has a weight on it because there isn't enough room in the crankcase for this weight to be on the crankshaft.

If the damper slips, the weight is now in the wrong position and will cause a vibration.