IRL, many ships, especially larger ones, often had unique characteristics that (at least up close) would identify them to a certain extent to experienced and knowledgeable captains. I agree with UltraVires that this should wait until we can customize ships and flags. This way we'd have other, more realistic ways of identifying (in)famous captains and ships.
Edit: This would also introduce a bit of a "false flag" concept into the PvP as well-known captains would need to modify their ships from what they usually sail with if they didn't want to be immediately recognized.