Concerning whether a shoal draft boat will survive in blue water -- Carleton Mitchell's famous Finnistere was a center-boarder designed by Olin Stephens. Finnistere won consecutive Bermuda races back when.
In sum, yes a deep fin is usually better, but that doesn't mean a shoal draft boat isn't seaworthy or can't go to weather.
Disclaimer -- I sail a P-33-2 with a winged keel that draws 4'2" and I haven't died yet.
