If the requirements are easy though, then there's no point in even locking the characters in the first place. I understand if they want to make something so hard to achieve that you get "bragging rights" for having it, but it should never be characters.
Fighting games should always be made with the tournament scene in mind too, and therefore all characters should be available from the get-go so that the event holders don't have to go through the tedious task of unlocking them on all of their systems. It works for normal play too. If I main Alpha, but my data gets corrupted one day, I then have to go through all of that hassle all over again before I can continue playing my MAIN CHARACTER. It's unacceptable.
I understand where you're coming from, but I really, really disagree. It all depends on what the developer is shooting for. After all, as seen by TN of the past, they haven't always made the game with the FGC in mind, and some of them still sold well anyway. However, I must agree that unlockable characters are a huge pain in the ass, but then again, even SSBB after SSBM's tournament scene had unlockable characters, same as fighting games.
Simply put, I don't think there should be unlock characters, unless the requirements are really easy, but I don't think that it should be to keep the tournament scene in mind too. To be completely honest, I hate how the FGC goes up in rage if a fighting game wants to use the Right Thumbstick for features. I think of fight sticks the same way as I think of Turtle Beaches/Tridents. They're tools to make the game much easier and efficient when mastered correctly. I've never liked that, and think that control wise, everyone should be on the same level. But I suppose that's an argument for another time.
Anyway, you're right, shouldn't be unlocks, have to agree, but I agree for a different reason than just the tournament scene, even the people that take the game very seriously but just play online have serious match-up problems if they can't train against a powerful character.