As a DM, if I was running a game where a substantial number of PCs or monsters were tiny, I would consider recentering the combat scale.
In other words, large=huge, medium=large, small=medium, tiny=small.
Not perfect due to the inconsistent scaling that exists between medium and small creatures.
I have actually played around with combat scale being dynamic, ie. the smallest size creature in the combat always takes up one square with a threatened area of one square, and anything bigger is scaled up accordingly. It is actually fun, a medium sized PC then actually FEELS like a giant when battling tiny creatures.
