It's hard to see what sort of tactics you can have when you're on a small island tho...............
You mean like having your big guns pointed at the sea when the threat is coming from the landside. I think the Singaporeans are well aware of the limitations of their geography and understand the need for the latest equipment. They have operated the F15 for years so the F35 is a logical upgrade. If the US offered the F22 they would probably have bought them.