Just a thought on yorker bowling at the end of the T20 world cup. I don't have any concrete evidence to back it up, but I'm wondering slightly if myself & others may have been too harsh on fast bowlers inability to consistently bowl yorkers in T20 cricket.
Since the 1st T20 world cup in 2007, the three best fast bowling yorker bowlers are still Malinga, Gul & Steyn. But Malinga is by far the most consistent - Gul & Steyn have about a 60/40 success/failure rate. Other fast bowlers in the world are simply poor/average at it & tend to try other variations to compensate.
I've always compared bowling in a T20 from overs 6-20 to the last 10 overs of the 50 overs game. Either that is too simplistic a view & bowling yorkers in T20 is harder than usual due to batsmen improvement or world quick bowlers have not done enough practice at the bowling like Malinga has done.
The best bowlers in T20 are essentially the spinners with variety, which is why the big three asian teams & West Indies have been the better T20 teams in these early years of the format.