IPL has been an average fare at best. So what about the commentators?? . Lets look at each one of them Individually

Greg Chappell: The most boring of the lot. Does not commit too many mistakes and most of the times is very frank with his opinions and correct with his analysis. No wonder he could not sustain as the Indian Coach.
Verdict: Take him out and replace him with Sidhu to boost up the entertainment.

Tony Cozier: Again someone who is not too entertaining. An average entertainer at best Tony Cozier has failed to spice up the event with his commentary.
Verdict: Can be dispensed with and replaced by "Venkatesh Prasad"( who i guess will receive the marching orders sooner or later)

Robin Jackman, Rameez Raja and L Sivaramakrishnan: Passable is the best word which best describes their performance as a commentators.
Verdict: Can be dispensed with

Ian Bishop: The "Professor Commentator" is fit only for the longer versions of this game and does not fit the bill for T20s.
Verdict:Send the professor back home.

Ravi Shastri: Wonderful entertainer. Whether it comes to wooing the crowd by speaking in the local language at the toss or speaking about the Cheerleaders he is excellent. Not to forget his loyalty, which he expresses by praising Lalit Modi at least 10 times in a game and keeps on asking the players about how it is to share the dressing room( Going by these commentators,I guess IPL is more about sharing dressing rooms)
Verdict:Get him some incentives

Sunil Gavaskar:Loyalty thy name is Sunil Gavaskar is the feeling one gets. "Well there is Lalit Modi", " Here is lalit modi", "Lalit Modi enjoying the action", "SRK is happy" and he speaks some cricket too in between.
Verdict: Bonus Candidate

Aamir Sohail: "Husky voice and Loads of Nonsense(read as entertainment)" captures Aamir Sohail. One example for that:" Wasim Jaffer holds the key for Bangalore"
Verdict: Bring on more such people. We want entertainment

Ranjit Fernando: Keeps the viewers on the edge of their seats by not completing the sentences at all. His way of structuring a sentence is "Start, pause, Start, Pause, End "
Verdict: Go Ranjit Go, Keep Going

Pommie Mbwanga: If he were a radio commentator then the listeners would be made to think that playing cricket leads to Hypertension.So excited he gets. I dont blame him. I guess his pay packet is linked to his ability to keep viewers engaged even when there are no contests, for which he goes crazy over trivial things. A loyal IPL servant.
Verdict: If he develops some of Aamir Sohail's trait or Arun Lal's to be more precise then it will be great.

Arun Lal: Undoubtedly the best of the lot. Seems to me like there is no limit to the humor which he can provide. It does call for an ability to keep uttering nonsense stuff and carrying off without improving at all. Arun has it in plenty. I wont quote a lot of them for then the length will become too much. All i will give is one statement made by this gr8 commentator.

(One of my friend gave the beginning of a story and asked the readers to complete it. Well i will be slightly different. I will give a sentence. Now you have to tell me the meaning of that , If u can)

"The bat speed on that occasion proving to be disastrous"

Verdict: 3 OR 4 more Arun Lals will make IPL a very entertaining watch for the TV audience.

The above list is based on the entertainment quotient alone. Sensibility and understanding of the game are not considered as the game itself is designed for Entertainment.