Actually, I wonder just how much this would be welcomed by Dominican-Americans. Depends on how the Census would do it, I guess.
If the Census just adds a category "Caribbean" without subcategories I'm not sure many Dominican-Americans would like it and identify themselves as "Caribbean" during the Census. I know many Dom-Ams that complain loudly that when average Americans hear the term "Caribbean" -- whether applied to food, music, art, or culture -- they think of Jamaica or some other portion of the English-speaking Caribbean. "That's not the Caribbean I know," these Dom-Ams assert. "Not my food, not my art, not my culture, not my language, not my mindset."
Point is, would Dom-Am respondents really prefer to be lumped in with the Jamaicans, Haitans, Trinidanians etc. as "Caribbean" instead of responding that they belong in current "Hispanic or Latino" category? I wonder...
Personally, I dislike the USG's obsession to divide and sub-divide the US population into more and more subsets and track them. In the last Census, our household was one of the unlucky ones picked for the extensive interviews. I hated it the whole long, emotionally exhausting, intrusive thing, my wife even more so. She got ticked off right at the start by being forced to characterize our twins as one ethnic category or another...