Personally, I don't believe alphanumeric callsigns are better than digits only when it comes to reducing confusion. Just think of all the alphanumeric tail numbers that fly around daily, plus it doesn't help if, for example, a certain UK airline that operates into Gatwick uses ABC12GW as a callsign. If other airlines come up with the same bright idea of choosing their callsigns after the airport the flight operates to or from ...
Where I work, I sometimes end up with callsigns like ABC787Y, DEF78DY, and GHI87Y which doesn|t do a lot more than tie up the tongues of everyone involved ...
