The big issue isn't exactly the Con loss honestly,though it contributes greatly.
If the Elf gave ANY racial traits of significance, the Con loss might actually be worth it.
Lack of Darkvision to make the better rogues(low level ones anyway), a hit to an already weak stat for casters, overridden weapon proficiencies for warriors. All it has going for it is the odd PrC/feat where the designer believed only elves are awesome enough for and those have a tendency to have the racial requirement blankoed out by DMs.
So yeah, they need something, without the con penalty, a little something, with, a lot of something.