The low of wave 4 is probably seen by now, and will not move much lower. (previously 1.28 was still possible)
- Q3 exports was down a massive 4.9%.
- Trump presidency that will render the current Transpafic Partnership (TPP) under discussion obsolete.
- Increasing competition from regional ports (such as iskandar malaysia), and China's Huge 'One Belt, One Road' initiative on increasing infrastructure investment
Years ahead Singapore will be in for the best of globalization, while other countries are increasingly de-globalizing. (As seen in the Philippines, Brexit and US election this year, including EU election in 2017) The 'open' policy will be worst off.
There's simply no way Singapore could impose levies and taxes, since it does not produce on its own and is unsustainable without foreign imports.
Regionally, ASEAN as a whole is dead. Malaysia, Brunei, and Philippines are moving increasingly closer to China. As a whole there is not really any leverage in the South China Sea at all.
The prime minister of Singapore, Lee Hsien Loong have pretty much left all his basket of eggs with the US and have proved to be disastrous so far.
China will have the last laugh regionally.