If the current version of Ovi maps would have automatic route recalculation, it would already be (just) usable for navigation imo. Sure, it would still lack a lot of features such as off-line address searching etc., but the basis would be there.

I always assumed the capability was in there, but not switched on because of anticipation towards licensing/marketing options. But now that it has become free, that limitation is gone. I'm (naively) hoping this will be switched on in the next firmware.