Danny the point you are missing is that the problem is Consistency. The exposed brain, the glass tube, dosen\'t \"match\" the overall theme of the game.
So while the game is a fantasy, you need to think about it this way. Do you think a game would be good if it had zombies, dragons, killer monkies, flying elephants, and talking bugs? The developers have choosen to stick to a theme within the fantasy universe, and in their eyes, your idea is too far fetched.
However, the idea of a large, wingless bird you can ride sounds cool. How about you remove the brain manipulation part, and the glyph part, and just made it a fast animal, that requires alot of taming to control (thus making them expensive, and for the noble class only.) I think the devs would like that alot more.