Offer option to only import "extra" address fields (info source, etc.) if completely new
If my import includes address fields including info source and IOM finds that address is already in RE - Don't change the info source on my existing address! (or at least give me the option to decide to do that or not)
Also if the address I am importing is in on a consituent but it is a former address and I am importing that address with a primary address flag (because someone gave me old data) do not take that old address and make it primary without prompting me. I'd consider that a significant change that I would like.
BTW - both of these still happen even after you select the "always ignore new address information" checked.