The problem with T-20 is 20 overs is not enough to formulate a strategy, be it batting or bowling. With batting it's keep hitting, and with bowling it's keep bowling a tight length and line. Also there is no element of shame involved. Oh,your team is all out at 80. No prob, all the batsmen were too aggressive it was bound to happen. Same thing with an opening spell of a bowler. Oh you went for 24 in the opening over, no problem, the batsmen is there to hit every ball for a boundary after all. There is no accountability.
Increasing the overs from 20 to 50 solves all these problems, and hence ODI is the best format of cricket. It allows strategy and also earns revenue.
Test cricket is the worst. From a marketing point of view, entertainment point of view; it is heading towards extinction soon. The fans are the most oblivious ,those who claim the great test rivalries between industrialized nations as examples of the format's greatness. What will they do when these nations pull the plug on test cricket 20-25 years from now? Surely they will rue the missed opportunity to focus solely on ODIS and stay one step ahead of of their competitors.