Most manga are like that. They start off with all this detail so that they can get more readers. Other manga-kas start off with really crap drawing skill - no offense to Mashima, Ookubo, and Kubo - and they get better as time goes on. Like for example, Naruto's original design had him with these super-complicated steampunk-type goggles, but Kishimoto said that they were too hard to draw and took them out. I think that that's what happened with Mashima.