This was a very unwelcome step. Right now, I'd say that Gambhir's form as a batsman is not that great, but his captaincy is still very good. Now see what they are doing. They are making the inexperienced Sreyas Iyer the captain, which will add unwanted pressure on him.
Ya not sure with this sudden step down when the Delhi requires a experience guy to lead from the front and Gambir when it comes to experience is the best and Shreyas on the other hand will the new and may find it difficult at times to take the hard decisions. Need to see how it goes for Delhi.