I suppose this shows how little I know about this stuff still. Not a lot of practical experience with leathers, more so just what I read.
For drape, Jerky and goat are perhaps the strongest contenders, because they were selected for their resemblance to WWII flight jacket hides, which had a nice draping quality, not stiff and creased like heavy jackets.
I like both types but I think from what you’ve mentioned, the A-2 hides are closer to ideal.