I have a feeling that both routes 400 and 402 will be withdrawn
in the near- to mid-future, to be replaced by other bus routes.
Quite likely, route 30 will be rerouted to ply the new Marina Bay
downtown once East Coast Parkway is realigned; there is also a high
chance routes around Marina Centre and Shenton Way will be extended
into the new downtown, especially after the bridge linking from
Marina Centre to Marina Bay is completed.
Some good possibilities:
Moving further into the future, I expect that Shenton Way bus
terminal and Marina Centre bus terminal to be closed down and
replaced by a new bus terminal or interchange in the Marina Bay
area, with all bus routes currently at these two places extended to
the new bus terminal. Alternatively, both bus terminals could
continue to exist, but the bus routes they serve will be swapped as
routes terminating at Shenton Way gets extended to Marina Centre
via Marina Bay, and vice versa.
Service 30 is most likely to ply the MCE when it opens. The
current service 30 provides a fast link between the south-west and
south-east by skipping the city area, if it is to be re-routed into
the new Marina Bay downtown calling at every stop along the route,
the purpose of the fast link will be defeated, so very high chance
it will be re-route to ply the MCE instead of entering the new
Marina Bay downtown.