I wouldn't want it released at the same time as the raids, I like having some time to prepare for and prog those without worrying about missing out. That said, 7.25 might be a little too long.

In my opinion, the field operation type content should be added halfway between X.0 and X.1 (about a month after the first Savage tier), and then updated/expanded in every odd-numbered patch (X.1, X.3, X.5).

That way we'd have some long term content added early in the expansion, adequate prep/prog time for each raid tier, and the odd numbered patches would offer some content that lasts more than 3 hours.