Wide (and flat)
- is slow in low winds
- is slower upwind (and usually isn't able to point as high as narrow boats)
- able to plan downwind (and then way faster)
- is more stable in what regards heel
- has more space inside
- is less harsh in wave movement
- has less wetted surface and therefore faster in the light
- points higher and faster
- heels a lot
If you consider ocean traveling with the tradewinds (most of the time downwind) and do not care of a light and simple interior, the wide french performance-cruisers are your choice. If you are going mainly upwind and looking for a traditional wodden interior you might look for a more traditional boat.
In neither case you should take a fat (but not wide&flat) cruiser like a Bavaria or a Beneteau: These are made for living, not for sailing...
I agree with most but big generalization like that are dangerous. For instance a narrower hull shape like the one of a VOR 65 is able to go faster planing downwind than an Open60, even if they had 65ft. The same with many other boats. Planing downwind has mostly to do with lightness and shape of the hull. The difference is that while on a narrower boat you will have to have a crew to have it in perfect balance, a beamy boat (Open 60 type) is much more forgiving, so forgiving that it can do that on autopilot, but it also has more drag and is therefore slower.
Of course, you are talking about boats with similar weight but it is convenient to point that as well that the wet surface is mostly a consequence of weight (and design of keel and rudder).
Also to point out that the situation were narrow boats are more effective is upwind with considerable sized waves. You are right when saying that normally a narrower boat can be faster in light wind but that difference can be pretty marginal and when the beamier boat is considerably lighter (and that happens many times) it is not always the case. Going upwind with considerable sized waves is where narrow boats really have a big advantage, even heavier ones due to wave drag that is much bigger in a beamy boat than in a narrow one.
Also in what regards Bavaria and Oceanis series (or any other main market boat) I do not agree that they are for living, since they sail pretty well, as well as in most cases older performance cruisers, but I agree that on their design program, living, interior space and cost have a bigger influence on the design criteria.
Regarding fast performance narrow boats, more than to the French performance cruisers I would look for the Danish, American or Italian ones, boats like the J 1boats, Luffe, Xp or NM yachts.