It seems like everyone has put their biases into play. Like JohnL I have resisted responding as in many ways it's like "What's better? Vanilla or chocolate."
The original question lacks specificity. The only parameter given was ocean cruising and a two person crew.
Without constraints there is no "too big." He didn't set a price
tag for purchase
or a price
tag for maintenance
or indicate who will clean and care for a 100+ foot boat. He did not specify that he needed to dock it.
With enough automation and redundancy in the automation a 100 foot boat is doable.
There is a couple here on a 51 footer. They manage fine however I would say the boat is all consuming. They do little else but maintain and sail the boat. They are constantly cleaning
and varnishing, painting, waxing and repairing. They start at the front and work to the back and then start at the front again.
Although a cat is probably the most practical, for me it's 38 foot mono-hull pilot house. Sloop