User blog comment:IamJakuhoRaikoben/Chapter 364: Tartarus Arc, Part 1: Sins and Sinners, Review./@comment-4047931-20131221024001/@comment-7418318-20131221183419

The problem with Lisanna, as I see it, is that she doesn't really serve any purpose in the story, ever since she "died".

Everything she can contribute is already being done by other FT members (Take-Over? Already got 3 other mages, 2 of them in FT; damsel in distress? foremost Lucy, but others too; cuty... I don't even want to start the list; barmaid? Mira and Kinana; love-triangle? Juvia+Lyon+Gray, Levy+Gajeel+JetDroy) and that makes her redundant. Her magic, her personality, her role, even her looks... everything's there already.

Even giving her siblings a heartache, like she's doing right now, is something they can do for/to each other without Lisanna, so unless something about her changes, she really serves no purpose at all, except for brightening up the background with her nice looks.

And that is why so many peope either hate her or don't feel anything at all for her.