I flew Emirates when they were originally in T1, and it wasn't a good experience, massively cramped and hot at boarding. The gate areas in T1 are too small to deal with large aircraft, including those at the end of pier C. Terminal 2 has a greater feeling of space in that respect.
At some point T1 is going to have to give, it is (along with FRA T1 and most of LHR) is old and horrible to use, though the recent refitment work has helped. The world is moving on.