definetly data toggle is deal breaker... in asia countries like india n lot other we dont have on contract devices..
every phone here is off contract n sim free... so anyone can any carrier sim he/she wants..
alse more than 60% ppls here r middle class n poor which basically uses low cost n mid range devices..
so these users can't afford unlimitted data plans.. almost everyone uses here limitted n very small amount of data packs..
so users use it to turn off data anytime to keep ther data till last day of data pack validity...
and access of data toggle by action center is very handy...
if every other OS provides this data toggle then why not ms done it for wp..
I mostly uses data and brightness toggle.. we dont have wifi here n even no free hotspots available here...
about on-contract carries like ur AT&T n other.. they have ther own control on ther os firmware.. if they blocks data sense then they definetly blocks data toggle in ther firmware if they dont want it in ther contracted devices...