I think it's a good idea, but I'd probably stick with 6-ball overs. In the past, places like Australia and South Africa used eight-ball overs. Ten-ball overs could speed up the game by cutting down on over changes, but they might also tire bowlers out more and change the way the game is played. Changing the game from 6-ball overs to something else would change the way the game is played and its history because 6-ball overs are now standard around the world and are deeply ingrained in cricket's rhythm and records.