Where do you draw the line between converting an adventure and redesigning it?
I've been thinking more about edition conversion after a discussion here last week, and I've run into a related problem:
At what point does a conversion stop being a conversion?
Suppose you're adapting a published adventure between two editions with substantially different encounter design. You can preserve the story, locations, NPCs, encounter objectives, and intended outcomes fairly easily. The difficult part is the mechanics. If a monster originally existed to pressure the back line, you could recreate that behavior. If an encounter was deliberately overwhelming, you can preserve that difficulty. If several variants of the same creature originally filled different battlefield roles, you can reproduce those distinctions.
But every time you add an ability or alter an encounter to reproduce its original function, you're technically moving farther away from a literal mechanical conversion. I've been using a principle of:
Preserve the published material wherever possible, then make the minimum mechanical changes necessary to reproduce the original encounter's intended function.
But "minimum necessary" is obviously subjective. So, I'm curious how other designers approach this.
Where do you draw the line between faithful adaptation and redesign?
Is trying to stay true to the original primarily about preserving the original rules, preserving the play experience, preserving authorial intent, or something else?