I disagree. Not all of us are going to quit. Most of the guild that I run will remain after the transfers and give it a go. After all, progression PvE might be a bit more challenging if you throw in another ~150ms. Whilst I have lost one of my closest friends due to this announcement, I'll still stick around for a time.
You can raid. Quite fine. At 180-200ms. It is by no stretch of the imagination impossible. A few weeks ago, I tanked NiM EC on a mobile broadband stick where I was experiencing ~300ms with rather frequent timeouts of ~8 seconds. It wasn't perfect (due to said timeouts), but it was achievable and overall an enjoyable run.
Now. Don't get me wrong, I disagree with the transfers. I would *much* rather see an APAC superserver. But it will take more than a migration to the Harbinger to kill this game for me. And it certainly won't kill Oceanic PvE progression. You might just have to recruit a few late-night American players to fill the gaps.