Looking for absolutes in a world rife with 'relatives' is a journey that's not likely to yield satisfaction. Some reading up front will help. Beth Leonard's book is a nice outline of considerations as well as a comparison of their first cruising boat and their 'ideal' boat:
Amazon.com: The Voyager's Handbook: The Essential Guide to Blue Water Cruising
And on the design front, Bob Perry's book:
Amazon.com: Yacht Design According to Perry eBook: Robert H. Perry: Kindle Store
You're 'blue water boat' also has to include which blue water you're planning to be in and the number of hours and miles you have in other boats. The 'other boats' part is invaluable in helping you determine what best matches your priorities, not to mention even having an idea what is and isn't important. Without this experience, you're left to rely on the preferences and limitation of others. One example, if I were heading down to Mexico, had a limited budget and wanted a 40' boat that would get me there quickly, I'd look for an Olson 40. If heading to northern or far southern climes, I'd look for something with a hard dodger (or have one added), went to weather well, and had appropriate tankage. Many boats fit that description. Where 'you' come in is how you like to sail. I like a boat that performs well. It doesn't have to be ultralight, but it can't be a tub. Others are completely fine sailing a tub that wouldn't even be on a personal shortlist, but both boats will do the job.