Actually I dont see Ran as weak. Firstly, for those who says she is weak because she is heavily influenced by Shinichi... what has being influenced got to do with her being weak??? You have got to understand the difference in culture in Japan and other parts of the world. At that time when Aoyama started writing DC, girls like Ran are considered beautiful.
Also, I dont feel that being very attached to Shinichi means she is weak. It is a perfectly normal reaction to someone you look up to. Maybe in western countries, people dont have that tradition, but in asian, Japan as well, many people live their lives by taking someone as a rolemodel. I dont think that Ran taking SHinichi as a rolemodel is something weak.
Regarding her character, I think she is a very strong girl. Being strong doesnt mean you have tons of bad guys chasing after you and you have to deal with all the possible cases of being killed. For Ran, I think the most difficult thing she has to deal with is to have to deal with her feelings of missing someone she really loves. You can say Haibara has to deal with her parents dead and her sister dead. But she is not without her share of being paranoid and overly sensitive sometimes, to a point she interferes with Conan's ideals.
In my point of view, people are most afraid of what they are uncertain, instead of what they are already certain. I dont think Ran would have been hurt this much if Shinichi have just died in that incident. She will get over it after some time but having her live knowing that Shinichi is somewhere else, but no idea where, and that he is coming back, but no idea when is a horrible torture. You're wanting to see someone so badly that you are now chasing after his shadow in an attempt to see the person. I think this is evidence of true love.
To love a person that much that even if so far and so long apart, your feelings still do not fray... Ran you have my support! Go go!
*Note: I like Haibara as a person better but I support RanXShinichi XD