Eh. Choosing titles is common in other games and I don't think a big deal? Some people just like the ones you earn early in, and as a cosmetic item, there's a good case (IMO) for making it user-selectable. But how about these as a compromise:
* Lock out the really early titles, say the first 3 levels. So you can choose any title from 4-10, but people will always know you didn't just buy the game today. The exact selectable range could be flexible.
* Prepend the title with a number, like say [10] Aeronaut. This is actually a bit more intuitive... I don't know how many people memorize the titles tables but I sure don't!