If they can reference events from the PT without a level of detail that invokes specific scenes/imagery/characterizations, then I would be satisfied.
For example...
Reference Palpatine's rise as an abuse of political power aided by the shroud of the dark side, but don't give us exposition about specific aspects of his plan. We shouldn't need to know that he was a senator from Naboo, or how he controlled both sides of the Clone Wars, or who all of his apprentices were, or that he fought Yoda and won, etc...
By all means discuss the the fall of the Jedi Order and blame that on their deep involvement in politics, but don't explain every detail about how Anakin was close to the Palpatine, don't use Order 66 by name, don't even mention that the jedi were painted as traitors, etc...
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In other words, if they must reference the PT, keep it in the form of general ideological overviews. Stay away from detailed exposition of past events, and make sure the plot doesn't rely on such exposition.
An extreme case of this might be something like this... if we have a scene where Ghost Anakin has to sit down and explain to his grandchildren the Story of Darth Plagueis, so they can learn more about whatever enemy they are facing. This level of exposition and relying on past events would be a slap in the face to any audience. Frankly, I would walk out of the theater.
Keep the references light, and use them sparingly.