Ironically, Kirito's and Inoda's relationship is actually quite natural (putting NTR logic aside). In real life, it's normal for a couple to have friends that the other partner doesn't necessarily care about. So, you might spend time together if needed, or just let them meet separately. That's how I see their relationship. Asuna seems to like Inoda as a friend, so Kirito just goes along with it, and he also doesn't see Inoda as a potential threat for various reasons, but mostly because of not being able to build up suspicion. From a developer's perspective, it opens up space for more interactions between Asuna and Inoda.
As for boosting Inoda's power over Kirito, I mean, yeah, from Inoda's POV maybe, but as a player, we know that since the introduction of the Admin, it's all thanks to her because of how game-breaking deleting Kirito's suspicion every day actually is. I still think that's the most immersion-destroying tool, period. That was the final straw for me to let it go completely, because it turned the main plot into a predetermined slideshow without any tension and character development.