ECLs are obviously difficult to adjudicate.
I think that the main function of ECLs today is to help avoiding the other players to feel cheated.
This means that, in that perspective, it is much better for en ECL to be too high then for it to be too low.
The important thing is that the ECL races should not upstage the normal races.
It is a rather poor system, but it's all we've got at the moment.
There's some hope that WotC may get a better version working for Tooth & Claw (the monster splatbook).
Until then, I would advise any DM who is not certain that he and his players are fully aware of the limitations of the ECL system, and that the ECL character probably will be less powerful than non-ECL characters, to go with the default situation - only allow standard races.
Boring, but there you have it.
And the next implementation level is that the players are allowed to start their characters at a certain level, as decided by the DM, 0xp (as is, again, the default), 1000 xp, or whatever.
IF that is not sufficent for a character of the race the player wants, well, sorry, you're not allowed to make a third level character either!