I don't think many are mutually exclusive. We want to make Chain settings independent of global settings so this suggests the interface should be in Edit Chains.
First, I would add in the missing formats and the missing export parameters. I think making Chains obey regions is less important now that Chains support arbitrary Nyquist code that can work on regions to some extent.
But we should do something to show Chains is not a forgotten feature, If formats and export parameters are hard, do something easier that is still reasonably popular.