It would have been nice to have him sooner, but as I said before, he was by no means necessary.
That may be true.
Ultimately, I don't think having Fenrir makes someone a better SMN;
That, however, is not.
Back in the heyday of rampant RMTing, all but the richest of WHMs leveled without Erase. But just like that WHM that did learn Erase at 32, that SMN with Fenrir, all other things equal, is better because he could do things SMN's without could not
The abilities he could do also happen to be the most useful abilities for the first half of leveling.
The schism created where Fenrir is a luxury is not because of his abilities, but because of the system he was put in. That nail analogy is a bad analogy because it assumes you can do those things in the first place, which isn't true. Although nowadays a skilled group of 5 players can be geared to the hilt and reasonably expect to win, that you have to be of significant level to fight him is the only reason people don't expect a SMN to have Fenrir at level 20.
No one is forcing a player to get Fenrir for those reasons, but claiming that a SMN without Fenrir is the equal of a SMN with, all other things considered, is simply not the case.