The airspace is small and there are lots of constraints, including altitudes. There are areas of which below a certain height belongs to Malaysia, Indonesia etc. If the weather is bad with big cells all around with everyone asking for deviation, I think they are already handling it pretty well, honestly.
Frustrating it may be for the guys at the holding point of 02C/20C, but if you're up there trying to land with whatever fuel you have I think you'd appreciate this gesture very much.
I do think that it's a bit inefficient though the separation between arrivals, they should have it done like HK!