Will Construct be able to export to Mac/Linux/XBOX/Flash/?
Maybe one day, but not for the forseeable future. Construct is developed for free by volunteers. It would effectively double our workload for each platform added. Right now the most effective way for us to work is to concentrate on one platform. However, Construct is open source, so if you can interest other developers in the work, they may be able to complete the work. There are also distant plans to better support this in Construct 2.