At the moment, Singapore is clearly the main naval and air power in the region, but I can see that eventually, Indonesia and Vietnam are going to come on top. I think its just a matter of time. Singapore can always rely on big daddy USA.
Singapore has a qualitative edge, no doubt, amigo. She can, by theory, hold out against enemies in a short war / operation. But the fact that she is an island (and a very tiny one at that), as well as dependent on water supply (from Malaysia), she cannot hold out against a long, protracted war. The Battle of Singapore in 1940 was an example of how a much qualitatively stronger and fielded British Army (144,000 strong) was defeated in the long run after a long and grueling protracted war with a much smaller Japanese Army (28,000 strong). Singapore , unlike Indonesia and Vietnam, lacks strategic depth, as well as lacks the man power.
Indonesia is a nation of over 256 million people. Vietnam is a nation of nearly 100 million people. Singapore is what? Only 5 million? The latter is puny compared to the formers.