Most of the women I'm friends with are in relationships with men that aren't me :) So me being maximally attractive to them may not make them happier. I would need more research on how to have the correct amount of attractiveness in platonic relationships.

Sure women like the attention of a very attractive man, but it could lead to jealousy (why is attractive man speaking to X and not me), unrequited lust and .strife in their existing relationships.

Perhaps a research on what women find creepy, and not doing that, would be more useful for making women happier in general.

Edit: There is also the problem that if you become more attractive you might make your male friends less happy as they get less attention. Raising the general attractiveness of your male social group is another possibility, but one that would require quite an oddly rational group.