I do think that adding ten or so provinces around the Pacific would be a grand idea, so that a few of the more important island chains can be represented. There was, for example, no New Caledonia or Solomon Islands in EU, and they are large enough that they should have been on the map. Tonga already was a large and organized kingdom by the EU2 period (even going as far as attempting to annex Fiji), and it wouldn't be at all out of place to have it as a new nation in EU2 (Hawaii, the only other large Polynesian nation, didn't organize until the very end of the EU2 period).