I live in a place where location trumps just about everything. On top of that, very few houses are individual, they tended to be built as groups, so there are a number of identical or slightly different houses. But people here tend to pay attention to the inside, and the amenities, and not so much what the exterior looks like. Like I said before, since you would be moving into a neighborhood that contained similar houses, I don't think there would be any benefit to spending money to change the essential character of the house. (Like there might be if the mansard was anomaly). It would make sense to make it look like the most pleasant-looking example of whatever it is. You might like it better on the outside if you change it, but it doesn't really benefit its position in the neighborhood. I am not sure that it would necessarily be any more difficult to sell than anything else in the neighborhood--because it fits in the neighborhood as is. Again I will cite robo's example of the house that was converted. I think when you really analyze the outcome, it doesn't look any better than the original. I think there is an initial reaction of "great they got rid of the mansard" but when you really look, I think the new look may actually be even more awkward than the old. It just references something that we are more used to. I've said it before, but I live in a pretty ugly house. There are four slightly different ones. I bought it because the architect understood floorplans and getting light into the interior. I could have a house that looked better on the outside in the same neighborhood, but it would be darker and more cobbled together inside. But the "improvements" that a couple of my neighbors have made only serve to make their houses look worse. They are trying to compensate for something but not in the right way, really. So I think if you are looking primarily at location, you should really consider how the houses you look at "feel" on the inside, and not so much the face that they present to the street. (Since it's a development with similar houses). You really want something that works well inside, where you are actually doing the living rather than something that looks good on the outside--if you can't have both.

What you didnt address here is what you would like to do with the bay window, and what you are going to do about the brickwork that will be missing if you make it smaller.

Paint the yellow a slate blue. Paint the garage door a bluish gray darker than the siding. That will go a long way toward changing the look of your house. I can't see your door. If the trees are in the way, cut lower branches until your door is visible. It's hard to see from the pic, but it looks like there's a shrub hiding your window. I'd transplant it. The trick to transplanting is to get a lot of the roots and then to water, water, water. You may want to move it in the spring.

I would leave the brick and do a major spring clean up. The landscaping needs a lot of help. The columns should be beefed up. They are way to spindly. Your gutters need to be cleaned out, before you are dealing with water damage. I can see all that debris from the trees, in the picture. Its a very cute house, and the brick look nice on the front of it. If I were a buyer, I would prefer the brick over painted.