Hougang South was closed due to the regulation that every town
should only have 1 bus interchange. This regulation has been
breached repeatedly by recent interchanges such as Compassvale,
Tampines Concourse, Yio Chu Kang being upgraded to an interchange,
and planned interchanges such as Tampines North and Buangkok.
I doubt that LTA will consider revamping Hougang South in near
future as Hougang Ctrl Int has just been expanded. But in the event
that HCI faces overcapacity issues again with new routes and fleet
additions, it might be possible for Hougang South to serve as an
extension to Hougang Ctrl. I'm not too optimistic, though,
considering that LTA mainly focuses on newly developed areas, and
Hougang is already a mature town.
Hougang is a really big area, with the highest population in the
north-east currently (but will be overtaken by Sengkang soon).
I also have a suggestion to merge 53M with 43M and start from
Hougang South.