crwkunt roll.
You will get your 2 min wake turbulence behind an A380 and 90 seconds behind the B748 from the roll. Any additional delay needs to be specified before entering the runway. You are not aware of atc intentions re an immediate roll with a lander at 7 miles. Perhaps the controller is attempting to release another departure before the lander? With the daily movement rate now at HK around 1100, there are many instances where airmanship can be improved. A quick line up and roll within 30 seconds of a take off clearance is one. Don't get to the holding point and say you want a 10 min wait for your slot at destination is another. Don't stop on the high speed exit with one landing behind is another. Don't pester the ground controller for a push back when you have been told to standby is another.. Congrats on the nostalga re the high speed descent and direct tracking, the daily rate at that time would have been less than 700.
Perhaps it is better if you do your job and let atc do theirs.