As for Lucy... Ehh... Early on she's really terrible. She comes into her own later on though. She IS just a summoner. So... she won't really be as good as Gray, Erza or Natsu. Her strength comes from her summons. Of course, the stronger her magic the stronger they will be. So she just needs to become stronger really...
I get that she IS a summoner, don't get me wrong. The issue is the fact that, as you stated exactly yourself, she is JUST a summoner. "JUST," only, nothing more.
I don't like that. :/
I'm not expecting that she'd have too much else. What I expect is her strength to be what she is, but I thought she might have some kind of other magics or things to use on the side as well. My view of her as of current is that she is very limited and that her strength is too great of a weakness. Perhaps I'm just more bothered by seeing this be a "fact" in the very first episode: 'Oh, I don't have my keys. I'm completely powerless and basically useless now.'
However, I won't really say much at the moment and I won't argue with you about my feelings because I am still so early on in the series. I don't know how anything works in Fairy Tail. I don't know the limits that mages have, et cetera. So yeah. That is why I decided I'd just try to sit quietly and progress more in the anime before I get too set on any thoughts or feelings.
I apologize if any of that is or sounds just... idk.. :///