Killing of ODI? Whether you like it or not, it's not like ODI Cricket was flourishing fruitfully and bringing in huge crowds.
I'm an avid cricket supporter, and with T20... well, it's obvious it has saved the entertainment aspect for the "happy-go-lucky" viewers if you will. It draws in a LOT more views and has essentially ensured that cricket remains afloat... the IPL is a huge success, and the Big Bash here in Australia did wonders for Fox Sports.
If I had to choose between ODI and T20, the cricket traditionalist in me goes ODI every time, but the supporter that wants to still be watching competitive cricket in years ahead, well, he goes the opposite way.