So you can remove land masses from the poles and the circumpolar regions, opening the poles to large scale air and water movement that will bring heat from the equator to the poles increasing not only the temperature at the poles but also global temperature equality. Now that means that there's increased landmass near the equator, more tropics, more deserts, a little more temperate land too but continental not maritime influence is going to be the primary driver of world climate, so day/night temperature fluctuations are going to be greater and the land is going to be generally cooler and drier; a bit like during the last ice age but with less land ice and higher sea levels.
Now I'm not certain by any means but I'm reasonably sure that even with greatly increased temperature equality you need to pump in more heat in the form of increased insolation to get a 15-20 degree bump. That's going to increase average global temperatures which means increases in: evaporation, cloud cover, rainfall, bigger and more violent storms, a narrower tropical band, hotter tropics with higher water turn over, wider desert bands, hotter deserts, drier deserts (all desertification will be made worse by continental climate dominance), larger steppes on the equatorial margins of the temperate zones, temperate zones that are a little narrower and much less productive than those we're used to (this is due to their northerly position, they get less solar energy and the lower water budget in continental areas). I'm pretty sure that's everything.
Interestingly enough any mountain ranges in the continental interiors are probably going to be permanently snowcapped and push glaciers down into the lowlands around them.