It does piss me off that after everything she's been through he's treating her like dirt.
I'm unsure about the love aspect, perhaps she does. And I'm sure it could blossom into a romance, but this anime takes a very very dark tone so I honestly believe that something mortifying happens such as.. wait for it..
Mikasa confesses her love for Eren and then gets KILLED.
If the anime then wants to keep it on a happy note, perhaps Eren secretely shares some Titan cells with/without her knowing. If not, *splat*