I think the instigator is both a good and necessary rule. Those who rail against it are either too young to remember pre-instigator hockey, or else have sepia-toned nostalgia for it.
With that said, here's how I would adjust it. If an instigation is in response to a cheap shot or dirty hit, waive the penalty. If it's not (as in the standard "jumping after a clean hit"), make the instigator a major and game misconduct in addition to the fight.
What we've seen in the last 10 years is a huge increase in guys getting jumped for daring to deliver a hard but clean hit. It's complete crap, and I have no idea why it is that on one hand we see complaining about the instigator but also complaining about jumping for a clean hit.