So we know sending every frame pixel by pixel is awfully slow. But that was never the goal. Goal was to send "draw this sprite here" commands.

And it does.

The Letters are already preloaded, so i just send "draw sprite 'W' on X/Y.

So making an animation like this is just a matter of. 

Drawing the letter sprite.
Delay a bit.
Draw a blank sprite over the old position.
Draw the letter on new position.
Copy Shadowbuffer

Easypeasy.

The Arduino function looks like:

void Scr_DrawSprite(char x, char y, char spr){
  Wire.beginTransmission(0x41);
  Wire.write(3);
  Wire.write(x);
  Wire.write(y);
  Wire.write(spr);
  Wire.endTransmission();
}

So i can just write

Scr_DrawSprite(30, 20, 'W');

In my Arduino code.

It seriously cant get any easier than that.