I thought very hard about this and reached the opposite conclusion. I definitely think far differently under different game speeds and an informal poll of folks found a similar opinion. Separating by game speed is also something that is done with great success for other game sites, so we definitely wanted it here… maybe in the future we can also add the board sizes, but that creates a really complex rating matrix. Perhaps an alternative would be to give you broken out statistics on how you play on different board sizes as opposed to a full broken-out rating for them.