That's where I've been for a few months: The work of prior gatekeepers now run through the middle of what we're responsible for. It feels like we bought a house online and when we showed up the kitchen is in one country and the bathroom is in another so we have to clear customs several times a day and we have to hold a summit with the friends of the previous owner if we want to change anything--even things in the interior. The architect of the reorg would never have done this if the natural boundaries had been a bit more apparent, i.e. as a list of repos to be assigned to the new teams.
I'd prefer large scale shifts to come by replacing an old repo with a new one (or one with two, or two with one, or by open sourcing one which you no longer care to maintain). Maybe that slows down the organizational rate of change, but if the alternative is pretending to have changed in a way which isn't actually sustainable, then maybe slowing down is better.
More recent commentators have noted a corollary - for software projects with a long lifetime of code reuse, such as Microsoft Windows, the structure of the code mirrors not only the communication structure of the organization which created the most recent release, but also the communication structures of every previous team which worked on that code.