Instead of manually sizing each tile, It would be interesting to have tiles expand or shrink depending on the usage or number of clicks. Is there by default such an autoresize feature available? Would be pretty useful on small screens like phones.
No the Windows 8 Start Screen is not designed to work this way. The size of the tiles is purely determined by what the user chooses for that tile and has two settings
Also note the Windows Start Screen has nothing to do with that of the Windows Phone Start Screen.