Actually, I would disagree re: Diamond service selection. There aren't many other options to gift OWE status like JAL Diamond can. AA and BA require a LOT of expensive J/F tickets to gift OWE.
As for crediting X fares, well you certainly get more AA miles but value of AA miles has decreased significantly ever since they went dynamic.
I prefer JAL to be more selective about how their fares accrue, instead of throwing miles at everyone and making awards impossible.