It find some of these responses interesting. If most of the posters actually believed what they posted, they would not even notice someone coming into Church with a robe on. But alas, we show our humility by judging what everyone else is doing.
To the OP, I personally would see no problem wearing the robe. I would find it far less offensive than some of the getups that I have seen in my years in Church. The cowl would be a bit over the top since it is the women that should have the head covered and not the man, but that is really about it. I think the issue is what is in your heart when you do it, not what is in everyone else heart. If everyone would take the time to tend their own garden, they would find themselves too busy to worry about what is going on in their neighbor's garden. But then again, we know that is not going to happen. I, too, prefer a robe. And fortunately, due to my position, my priest allows me to wear my black Gibi when I serve in the church. I don't know why, but I have always felt closer to God when I wear it. I think that there is a lot to be said about wearing special attire before God, and I believe that the Coptics are way ahead of us in this regard. It has nothing to do with what other people think. And, if one of our good Christians want to judge you for being prideful, let them. The sin is on them, not you. On the other hand, you should get the blessing of your priest regarding the matter. Doing something in disobedience is never good. If my priest told me that I could not wear my Gibi, I would not. I would not be happy about it, but that would be my problem to deal with and not that of anyone else.