Nah, that's simply what the devs want. I don't care if he's a sissy but I wish there were a lot more than like 5 topping scenes in the whole game, animated or not, especially with true females like the Nurse or Brothel Madam (seriously what a waste!). Game is great and unique, but frustrating overall and not what most people will look for.
Making Hiro top somebody kills his whole character. He's very submissive and lets people get a hang of him. If he has to resist and fight enemies, he has to, but it takes all his bravery, and as soon as everything goes wrong, he will break, and people will humiliate him to the lowest point. Making him pin and top strong characters unfortunately is going to ruin it.
There are other submissive guys, Kylira and Trudy, who are meant to be a viable option for Hiro to top because they just don't resist at all. And it could be a good idea to let Hiro do more naughty dom stuff with them. But Kylira already has inn scenes for both modes. So mostly it's Trudy's turn.
Otherwise we need a completely different playable character, and I doubt Evoker will top anybody. Or, idk, Amazonian position is an option for Hiro...