We humans have a grand proclivity to categorize most anything. And sailors are not exempt from this categorizing disorder. We do categorize in order to facilitate communication, however, it often impedes discussion. Witness this thread. Loosely placed in the ever popular "Is this a Bluewater Boat?" category.
For the most part we can agree on the definition of a boat, even the
Supreme Court has ruled on this. The problem is "blue water." Each of us seems to have a different working definition of "Bluewater boat." When I think of a Bluewater boat, I think of a boat that can safely and comfortably sail for multiple weeks hundreds to thousands of miles off shore, such as a run from Panama to the Marquesas. Others may think of a 5 day passage from Newport to Bermuda as being a Bluewater cruise. And so our reponses to the original question, "Is this a Bluewater Boat?" are often at odds with each other.
Let me humbly suggest a different approach.
Begin with an honest appraisal of one's goals, dreams, skills, resources, and tolerance for discomfort. Don't rely the idyllic scenes in so many YouTube sailor videos. The honest ones share the good and the bad experiences.
From this, do the research on what is needed for the sailing you want to do and the conditions that you might end up sailing in. Preparation for a circumnavigation of Newfoundland is much different than preparing for a circumnavigation of Grenada.
Look at the longest passages you intend to make, what is necessary for those passages? A 4 day passage to Bermuda is much different than a 4 week passage to Tahiti.
Finally make a list of essential characteristics. As the list of potential boats becomes smaller, there will be more compromises and trade-offs. Go back to step one and reconsider the options.
Ask questions, and when someone says, this boat fits or doesn't fit the category, ask why and ask what is their definition of "Bluewater boat."
To re-answer the OP's question, with my conception of a Bluewater boat, the O'day 34 is not a Bluewater boat. It is not a boat that is designed to spend weeks far offshore and be subject to the kinds of conditions that develop in the open ocean. Outfitting an O'Day to meet those kinds of conditions would introduce a number of complications.
Is the O'Day 34 capable of a 5 day sail to Bermuda in decent weather, probably if the boat's rigging and systems are in good condition. Would it be comfortable and safe for making a 2 week passage from Halifax to Road Town? I think not. Is the boat capable of taking the Island Hopping from the Bahamas, to the DR, to Puerto Rico and then the BVI, yes it could Those are all relatively short passages of a couple of days.
"A luxuriously comfortable and practical offshore cruiser"
Marketing hype. What is O'Day's definition of offshore? In my thinking, Offshore is more than a day's sail to a safe harbor, or somewhere greater than about 150 miles off shore.