No I think you are right in that its fair to say her personality and development has a lot to do with her learning to trust other people/groups. I can also agree that it is most likely their intentions with Michonne. I just think their intentions and what is being portrayed once the cameras start rolling are different. It's like as soon as they start to make an significant break through with her they deviate into left field again. She feels half completed to me, like the writers got lazy or just assumed we would fill in the pieces by ourselves to make her complete.
You mentioned some scenes in your last post, like her reaction to Penny. I felt they could have went farther with that. I thought that was going to be a soft spot for her so I was actually surprised when instead of hesitating once she realized who Penny was to the Gov she ran her sword through Penny like it was nothing. Considering in the comics who the walkers she kept with her were I was thrown a bit off. Although I know she made quick work of them in the beginning of the series, we know she kept them with her for some emotional reason as she didn't realize the walker-smell-deterrent until later. Not that I felt bad for the Gov or didn't think he deserved it but I thought at least that would be a crack in her tough exterior. Just feels like with scenes like these the writers are missing their chance to develop her more.