I was basing this off a steeper Protection curve, since we're trying to replace that.
For every level, .5% chance for an attack to be taken by an enemy minion. At an effect of (30), blows made against the minion would have a 15% chance to hit an enemy minion (preferably not the attacker).
minion A minion X
minion B vs. minion Y
minA has FoW trained to (30)
minX attacks A, B, C for 10,000 damage each
minA has a 15% chance to avoid damage, which would hit minY instead.
My apologies if this is impossible to follow ^.^