T20s will always be close - because of the duration of the game. T20 overs are too little for 11 players, therefore the gap between teams reduces. Also, no one is out of T20 in most cases; in changes in every overs. On contrary, in Test better teams has more better individuals and every player can come into the game at some stage (for example that WI or AUS side had 11 greats, and some ATGs playing together - IND/PAK/ENG probably had 2/3/4 players who could have got into those XI ).
By maths, 1 over in T20 is 5% of the innings - so one good over, can cover up to 10, even 20% of the game from no where (Kartik recently recovered 100% in one over
); which is near impossible in ODI. It's more surprising for me if any T20 ends in more than 10% gap (that's roughly 2 overs or 18/19 runs). It's cheap but instant entertainment - why people are wasting time to figure out food value of pop corn?
Besides, IPL (any PL/SL) is draft system - on papers, every team is almost equal. In regional cricket, talent isn't equally distributed, while T20 leagues' expenses are bounded by upper & lower limits, therefore sugar dads can't serve cheque free books (not like soccer, where Sheikh Mansoor can buy Pep some of his class & genius...); here every game should be close by default. For the sake of saying, instead of T20, had IPL teams (any T20 leagues) played List A or FC Games; I am sure most of the games would have been very close there as well.
) as captain. 
