Except you can't use the existence of the Commonwealth as a justification for annexation because the Commonwealth was explicitly created as a transitional government for the eventual independence of the Philippines. We even signed a treaty in which we explicitly relinquished all claims of sovereignty over the Philippine Islands. Though the Treaty of Manila did grant us basing rights.
Re-establishing those bases and a friendly Filipino government? Sure. But if one of your reasons for justifying the annexation is the presence of English speakers you might as well have the Enclave annex Australia, New Zealand, Britain, and Ireland.
Like, I know it's kind of goofy when I want the Enclave to eventually encompass all of the Americas . . . But annexing the Philippines still feels weird to me when, pretty much from the moment we came into possession of those islands, we intended to prepare them for independence.