Volug, Ranulf, Janaff, Ulki, Vika, Muarim, and Nealuchi are among the best units in their parts. Not everyone needs to be an amazing endgame unit.
Lethe, Lyre, and Kyza are the only laguz that are straight up bad. And even then, Kyza is amazing when pumped with stat boosters since he doesn't have a shitty cat gauge.
Kurth will never reach SS strike, but he's incredibly easy to get up to speed in 4-E-1 with Paragon/Resolve.