Erk does better than most of the cast. Saying "she's worse than a high tier!" doesn't mean much. Now, bringing up that whether she's worse than Karla or not is/was a hot debate actually means something.
And as for FE6 having fewer chapters, that's only true if you count LM. If you don't count Lyn Mode, then FE7 has ~21 not including Gaidens. I can only count ~5 Gaidens off the top of my head, so that pushes it up to ~25 chapters. That's only more than FE6 if you don't go to any Gaidens.
Lots of these comparisons are pointless. First off, Lilina's durability. Let's look at them come endgame... (levels are probably inflated)
15/0 Nino
HP: 24.5
MAG: 12
SKL: 13.5
SPD: 17
LUK: 14.5
DEF: 5.5
RES: 12
20/10 Lilina
HP: 31.6
MAG: 29
SKL: 13.6
SPD: 16.8
LUK: 18
DEF: 5.8
RES: 18.8
Well, I doubt that Nino's .2 SPD outweighs Lilina's 17 MAG.
Defensively? 7.1 HP, .3 DEF, 6.8 RES, 3.1 AVO, and 3.5 CEV vs. nothing.
Hmm. Well that's not obvious. And relative to the other mages come endgame...
Lilina vs. Lugh
Lugh: 2.4 HP, 7.4 SKL, 4.2 SPD, 3.4 DEF
Lilina: 9.8 MAG, 3.2 LUK, 3.4 RES
Depending on what Lugh's speed does, you could possibly say Lilina>Lugh for endgame.
Now for Nino vs. Erk
Erk: 17.7 HP, 5.2 MAG, 3.7 SKL, 4 SPD, 5 DEF, 6.2 RES
Nino: 3.1 LUK
So, he has significantly better durability, better AVO and HIT, more damage per hit, and more doubling. Nino has... 3 more CEV? Which hardly matters?
I don't see how Nino could possibly be better than Lilina.
Est <_<