What if Earth had no large oceans, but many smaller seas?

Imagine a planet that is more or less identical to our Earth, but the continents are structured to create many large seas instead of our arge oceans. Thus, we'd have seas like the Mediterranean, the Black Sea, the British Sea, the Sea of Japan, the South China Sea, New Guinea Sea, the Caspian Sea, etc. In return, the terrain outside these seas would be more or less landlocked with the largest bodies of saltwater being seas of the size of the Great Lakes in North America.<br><br>How would this affect the climate and weather of this hypothetical planet? Because, it appears to me that such a configuration would create many smaller climate zones, particularly in the south of this hypothetical planet where you would have a pseudo archipelago structure of landmasses and smaller seas. And smaller seas tend to create the kind of climatic (and geological) diversity you find in the Mediterranean.<br><br>Also, how would these seas affect the habitability of the planet? On one hand, you have many more coastlines with the upsides of having more fishable waters and navigable rivers due to the seas being closer together. On the other hand, you would not have the same level of heat distribution across the globe because the smaller seas would not be able to mitigate extreme climate phenomena in the same way as our oceans do. For example, hurricanes tend to form over warm waters and dissipate once they hit colder waters. With only seas, there is more landmass breaking up warm waters, which may prevent a hurricane from ever forming, but you also don't have a cold ocean to stop such a hurricane. And this may lead to more extreme weather events on land.