Their sales are great - I'll buy advanced tickets when they are close to free (on points or cash), fees & taxes only. I'd sign up for their BIG program, you often get 24h advanced window on sales - many of the best deals will be gone by the time they are available to general public.
Also, the ASEAN pass now allows you to see availability BEFORE you buy, so you can put a longer trip around SE Asia together for cheap (review here).
And many routes are still cheap on short notice - that's great for spur of the moment - but doesn't mean the sales are bad...