So far I have been quite impressed with the format. I agree that the key is a wicket with something for the bowlers. The ideal game is one where the par score is around 150.
20/20 games seem to produce a lot of terrific counter-attacking cricket where a batsman or a bowler can turn around the game in a few overs. Think of Uthappa against Pakistan or Vettori against India.
Relative to ODI's 20/20 may actually see more genuine bowlers compared to bits and pieces players. This is because part-time bowlers are much more difficult to hide and because you would back your top 6 bats to use most of the 20 overs.
Anyway whether or not you like the format, I think 20/20 is here to stay. The India-Pakistan game alone may have created hundreds of millions of fans.
One big benefit I think will be that domestic cricket will become much more viable in the future as a spectator sport . From the commercial point of view, cricket does need a format where spectators can get a result in an evening like most other sports. If domestic cricket becomes financially viable that will mean a better living for a lot more cricketers.
Will 20/20 hurt test cricket? Maybe but test cricket seems to have survived ODI's fairly well and my guess is that it will survive this as well. And we can't rule out some 20/20 fans becoming converts to tests especially as they get older.