Dark_Messiah said:
Lucy aint useless, you can see eclipse arc that she aint just standing waiting for someone to close the door, even gave Natsu an idea to eat Atlas, against Franmalt she freed Natsu from being absorbed .. Also she aint weak 'Luck' is strength..
There's a difference between character strength and pragmatic use in combat.
We know she can inspire people and we have seen it in action before(hell didn't she at some point just outright told Natsu and Gray to shut up and coordinated pretty much whole guild to stop fighting in between themselves in order to go for the goal? Yes she did).
The problem is that combat wise she can't match(not until this power-up that is) up to the other lead in terms of performance.
If all you can do in a shonen manga is to inspire other people, you won't do much. Not to mention its quite a sexist portrayal if a female lead does nothing but inspire others.
With this she can do both.