Well... one thing you can do about Alizea is work more on the reaction people have TO her, and how she developes with it. If she's so ideally adorable and with such a torrid past (and still a nice person even though no one understands her pain) there are bound to be characters who have problems with her because of it.
Maybe she, herself, could on some level be aware of the hypocrisy of not wanting to believe people COULD understand her because it would isolate her less. Maybe, if she's a goody two-shoes, she could be confronted with how extreme goodwill can be hurtful to other people.

If SHE cannot be changed too much, then work with her environment and tweak up the realism-factor. From your fanfics I've seen you deal with a number of topics on a mature and realistic bent, you're good with nuances and dealing with - oh noes! - 'the unspoken' in relationships. Maybe you could take it from there?

Ugh, this sounds very ranty and doesn't make much sense, but I hope it helped a little, or was food for thought, at least. :)