Chef's is most definitely not romantic in any way. I agree the tables are far too close together -- we felt we could eat off the plates of our neighbors at the next table as easily as we could eat off our own. The food is only fair, too.
Shula's has wonderful steaks -- the best on property. But, it too isn't very romantic. We find it's usually filled with heavy drinking conventioneers on expense accounts. Sometimes we manage a quiet table in the corner if we go on a night when the hotel is between conventions, but that is pure chance. So we go there when we want great steaks and don't care about atmosphere.
We haven't been to BlueZoo, but given how unromantic your other two choices are, that's the one I'd pick.
Other suggestions: Victoria & Alberts (best restaurant on property, wonderfully romantic atmosphere), Artist Point (so long as you go late), Jiko (again, only if you go late). Narcoosee's can be nice if you go late. Are you sensing a theme here? Bistro de Paris on the second floor of the Epcot building where Chef's is located is another idea. We haven't tried Il Mulino, but look forward to it.
Frankly, really romantic restaurants are in rather short supply at WDW, IMO.