*Temporarily* unsubbing and a permanent deluge of male viera threads might help
The development team certainly deserves significant rebuke for its decision to neglect the male viera. I can hardly think of a worse isolated product decision SE has made.
However, a permanent unsub simply removes a person from an otherwise quite good game, a large part of the value of which is sustained by network effects. Moreover, it is not like you have a bunch of like games to pick from (feel free to make suggestions).
And as for many of these threads, most official forum responses seem to be in Japanese or only after sustained demand.
This is an imperfect market without comparable goods, so it will take a combination of voice and exit - your ability to dialog with the developer (which they barely notice, but is relatively articulate), and your ability to leave your relationship with them (which is more noticeable, but less articulate).