Don't come to Emirates if all you are after is a quick command. If you join now it isn't likely to be that quick and you will still be in Dubai, with the 92 hour rosters and all that entails, while you are waiting. You will end up becoming bitter an twisted as you (possibly) get passed over for command because you are on the wrong fleet or they bring in DECs. In answer to a question above they use DECs because it is cheaper and faster than upgrading an F/O and training his replacement- there have been times in the past, and doubtless will be again, when the training department is running flat out and still can't put the required numbers through the system. DECs are here to stay, just accept it.
Come to Emirates and Dubai for the long term, the lifestyle, the climate, the destinations and the job security. The command will come eventually.