As much as I have been a supporter of T20 cricket, an annual T20 international league would be overkill and kill the excitement of the format just like ICC has done for ODIs and Tests with poor scheduling.
I am, however, all for a qualification route to the T20 WC that will involve a large number of cricket nations (Full, Associates + more). An example would be to take 24 teams, split into groups of 6 where each team can play each other multiple times home and away and the top 4 from each team qualify to the T20 World cup. this will give countries like AFG, ARG, NAM etc. matches with the big teams and help boost cricket excitement around the globe.
Follow you I will but you have to give me something to look forward to as well.