Command is normally strictly on seniority, subject to suitability, and a minimum total time of 4500 hours. The national cadet pilots join the same seniority list as the expats, and as they have only 300 hours when they join, they take about six years to achieve command. Expats are making it in 2 and a bit years at present, due to the rapid expansion. Emirates treats its pilots well, and as a result get a lot of loyalty in return.
Worth a go for the right type! Good luck.