Entering my address via a traditional form drives me crazy:
This is no problem. As soon as the autocomplete pops up, people will understand.
Yeah, you should find a way to migrate it, or put that field on top of the address. If it's already entered, people won't think they'll have to enter it again.
When your store grows, you need chaching. Anyway. At all levels.
I agree. Just fix some minor issues. :-)