I've got an iPhone 4 which I recently updated to iOS6, and yep, lost my nice map for the newer, sometimes errant, Apple Map. Got the Google Map browser deal, but it's far from the same as the old map I used to have.
They'll get it working, I have faith in that. I don't use it as much as some do, with the good ol' Garmin unit being my main nav source, but did use the map app a lot to double check a route, set compass direction for parking to the north, etc.
I suspect I'll go for the iPhone 5 after the first of the year, and am debating whether to just buy it outright so as not to lose my grandfathered Verizon unlimited data, or go for the upgrade and lose the unlimited data. I wish the Verizon iPhone had removable sim cards instead of flash memory, as it would be much easier to transfer the acct to a new phone, and gift my i4 to my kid.