The basics are the planet is larger in both mass and size, but lower in density than the Earth.
In a previous question I asked about methods of reducing said Density which involved thickening the mantle and crust and it lead me to another question: how would a thicker crust and mantle affect tectonic activity?
Assuming that for all other intents and purposes, tectonics are basically function like on Earth, how would the thicker crust change the way plates behave? ie. Would there be fewer, slower plates or vice versa, and would it affect volcanic activity (eg. volcanoes are less likely because there is more material the magma has to rise through, or perhaps the pressure is more likely to mount causing more explosive eruptions)
I'd be interested to know the results.