As a full-time house flipper of higher end homes, I've seen all types of design challenges. Often, my job is to remove or mitigate bad design decisions, where possible.
Personally, I believe that a main sink in an island is a really bad idea in most instances, however, there are times when it's the best fit. Doing dishes is a necessary and sometimes mundane task. Having good sight lines to either look out the window, see a TV or being able to interact with others may be an important consideration. Reversing this we're really saying: Try not to put your main sink against a boring flat wall if it can be helped. Pick a more tolerable spot.
Designers love the look of a sink in the island, but one must ask are you building a "show kitchen" or a "working kitchen"? Look at all of the empty show kitchen pictures in this thread. We only seen one instance of a kitchen in use. If you search for the pros and cons of a main island sink, you'll never see the designers mention the word "clutter".
Let's address clutter around a working main sink. Dirty dishes need to go somewhere. Drying dishes need to go somewhere. Either you care about clutter or you don't. If you don't, you have many more options available. All main sinks have a clutter issue, so your next question is what are my clutter sight lines? If your island opens to your main living room, do you want these dishes always prominently displayed for you and your guests? A common configuration for adjoining living areas is to reduce the visibility to the working areas, while still keeping the openness. This is often done by using a 2 tiered configuration - an upper bar top and a lower working surface. The upper tier's job is to hide the clutter from the living area and then bar stools make that counter top usable.
If you have a galley kitchen, or an otherwise isolated kitchen space, then the omnipresent clutter is not as much an issue. There is some expectation that there will be dishes in the kitchen and if you are outside the kitchen, it's not visible.
Clutter in working kitchen is expected and frankly not the issue being discussed. Most of the time, the kitchen is idle (not working) and yet there may still be dirty dishes or drying dishes out. What are your sight lines and do you care?
A technical note for any potential home builders. All sinks need a viable air supply, which is typically a vertical vent stack in the wall that protrudes thru your roof. When putting in an island sink, a vent stack is not possible. Search for "kitchen island plumbing loop" to see pictures.
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Cab color, dark island
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