The closed Kai Tak airport is of very backward 1960's terminal design, with only 10 fixed boarding gates, hence most passengers had to board on an aircraft via shuttle buses & movable boarding ladders. What a joke for such rich & advanced city of Hong Kong to have such backward airport until 1998, when Chek Lap Kok airport was opened!
In fact the Hong Kong Government planned a new airport as far as early 1980's, but the plan was suspended until early 1990's because of Hong Kong economy recession in early 1980's. But the traffic of Kai Tak airport grew rapidly from mid-1980's, thus making the airport having not enough fixed boarding gates.
So I think the Government could do better by reclaiming some land on the southwest side of the Kai Tak runway early in 1970's, to make land available for larger passenger terminals & hence more fixed boarding gates, thus providing better passenger service & shorter turnaround time until the opening of the new airport.