Title. Is there a reason beyond just laziness?
And please don't say "we are working on adding it and it will be available on the new client which will go live 'Soon™' "
It's not laziness, it's organizational issues. Riot can only manage so many employees, and the amount they have is only enough to get out just a few major changes a year. They're doing their best.
I agree that their presentation of game mechanics and detailed champion stats is almost embarrassingly bad.
That said, having it accessible in the client itself vs. on their website likely has very little value add for most players.
