I'm confused as to what there is not to agree with. It's genuinely how we all came to be. While there are exceptions certainly (never said inevitably), to say that starting a family is the expected next/last step in most relationships does not seem like a particularly subjective statement. It is the biological point of romances. Of course not all npcs would not opt into such a thing with Steele as they may have reasons why they don't want kids, but it is where you'd generally expect relationships to eventually go with fleshed out characters unless there is a stated reason otherwise. And in a game like this where everyone is breeding like bunnies, where you literally have stats tied to it and where ridiculous amounts of money was invested before you even start in preparation of such an outcome, it is more than a little odd to set off and find almost no procreation results without explanation, even by accident.
As for Hughes, you say that because you only know the final product of the character with all his depth. That is why you cannot separate him from fatherhood. But objectively speaking, they could have cut her out and told the story without making almost any changes. She enriched it but she was not actually integral to the story or character at all. He already had plenty of depth and motivations to do everything he did with his wife, the elrics, winry, roy, etc. The pregnancy and fatherhood just added more layers to his character and his relationships.
Also I find it odd that there is concern with kids being used as a gameplay element. They're not real. This is a game where you can literally kill, take sexual advantage and enslave various npcs. Being concerned that Steele is not taking individual care of the kids himself directly is an odd place to draw the moral line. Especially given they get everything they could ever need in that state of the art nursery system. Rich businessmen use such (much less advanced) services in our society too. It's not exactly evil. Not to mention, the offspring are only at best half human. That means often time their normal life is far different than the standards you're holding them up to. For example, if we're talking about breeding with a zil, which are basically like giant bees, they would not expect individual care of their children by their parents. This type of life away from parents is pretty standard for many species that are bred in large numbers. Those that aren't could be a bit more personalized touch like Sophie from CoC.