From a strictly technical standpoint, if the world is indeed flat then it
will not be subject to the normal forces that affect the real world (such
as the coriolis effect and hadley cells, etc.) that create the climate
patterns we have here.

1. Is like a 50% bigger than earth.

Is that true both E/W and N/S, so that if, for instance, you sail
too far north, you are suddenly in the south? If that's the case then
your flat world is, in fact, being subject to some pretty interesting
geometry.
2. That's the power of the gods, as they don`t wanna "material" beings on other planes.

(I guess this implies that in summer, the sun-god travels more
over the northern sky and in winter more over the southern sky.)
3. You get it. XD