To answer your question that you first asked. The main reason why people don't like Twenty20 cricket, is due to over kill of the format that seems to be taking place. People were happy with one off matches to start a series or tour. A World Cup/Championship is many people eyes is just over the top.
Some people are afraid that Twenty20 will take the place of ODI cricket. Many people believe there not enough room for all three formats and one has to go. With the potential extra money Twenty20 can raise it might reduce the number of Test matches and ODIs for more Twenty20 matches. I doubt this will ever happen personally, but i see nothing wrong with a couple extra Twenty20 matches instead of the boring 7 match ODIs, worse thing that ever happen to cricket IMO. But if there is limit to those series, there also might be more 2-Test Match series. The more Twenty20 Cricket, is likely to mean the less ODIs and Test unforuntely, or either some ridicoulous player burn outs, with too many matches. There are ways to have all three with a decent schedule, but the boards are too concerned with money to consider player burn outs.
The other issue is the nature of the games, and believe that the games are too batter oriented. A lot of matches seem one sides and over within 30 overs, there hasn't been many matches at International level that have gone the full distance. Also there a believe that the matches are very similar. They all seem to follow the same pattern and there much variety in the matches.
The other factor is the use of bowl off to decide matches. This is dire i have to admitt. Rather a tie any day of the week.
Personally I still think Twenty20 has its place in cricket. But i would be surprised if the boards and ICC don't kill it in the search for more money and quick money.
I think that answered your question, maybe.