The actual quote appears to have been:
Yoshida:
There are many players who have finished with Alexander: The Creator Turn 4 (Savage), so we made the difficulty a bit higher this time. You could beat Sophia if you followed someone who knew what they were doing. This time, you will need to put a bit more effort in. The other content of the patch is quite on the casual side, so…
Source.

I can see why someone would take that as an implication that Zurvan Extreme would be designed as content for people who've beaten A12S, but he also didn't technically say that that's the level of difficulty they were going for, just that they "made the difficulty a bit higher this time."