From now through May 11, 2023, you can convert partner points into Asia Miles and receive up to a 55% bonus.
Among the participating partners, transfers from Shangri-La points, IHG, and Esso points come with a 25% bonus.
On top of that, if you have not transferred points from any of these three programs into Asia Miles between April 1, 2022 and April 11, 2023, you can earn an additional 25% bonus. That means the effective IHG transfer ratio improves to 10:3.
Personally, I think IHG is the only one here that is somewhat worth considering. Since you can consistently buy IHG points at 0.5c/p, that works out to acquiring Asia Miles at about 1.66c/p. If you have an immediate use in mind, this could be worth considering. But if you are just speculatively stockpiling miles, the transfer ratio is still not especially compelling.