If you're sick of useless male MCs (common in harem and shounen romance), Akatsuki is a refreshing male lead. Like Keima of World God Only Knows, he truly cares for the girls and knows how to handle a harem. Like Issei of Highschool DxD, he is perverted, but can always be relied upon to save the world and the girls he loves.
I've watched the anime and read the translated light novels volume 4 and 5. The story only picked up and showed the depth of the characters after the revelations in volume 5. This is common in the fantasy genre that needs time for world building and time to slowly build backstory. Seriously, I think the anime was only the beginning arc of the story (LN volumes 1-3). Its also no surprise that the manga that barely covers volume 1 cannot show enough depth. [as of 18 Feb 2015]
I estimate that around a hundred chapters from now, will we see the MC's battle with the several enemies, much more powerful than him. Call them level 100. However, in the genre of battle mangas, the author needs to show enemies one level at a time. If the MC immediately triumphs over the strongest person in the world, that wouldn't be fun. The story will end quickly! We wouldn't be able to savor the battles with mid-level characters, at level 30 or 50 for example.
I think the fanservice is standard in the genre, but the author uses it well. Usually, virgin MCs stumble into the scene then get punched to the stars. Hentai MCs would escalate things quickly. The MC of this story uses it to loosen up the stress in the girls. In self defense, he also strips girls instead of physically hurting them. Hoho, the pleasure he induces can even make girls interested in the fanservice. The author even strategically places the fanservice in points where the story is very tense in order to diffuse the heavy mood.
I repeat, this is NOT a Gary Stu or pointlessly overpowered MC. The story simply starts at the midpoint, after he has already overcome his powerlessness. He will then fight several "false" heroes. I think the story's true theme is exploring what it means to be a true hero. In Akitsuki's actions, attitude, and beliefs, he'll demonstrate his underlying principles/values (aesthetics) that make up the 'rogue' hero.