It looks like Star Wars Episode 7 may hit its expected 2015 release date, but instead of its traditional May release it will be a Christmas time release. According to the Latino Review, the rumored principal photography start date is January 21, 2015 to make a Christmas 2015 release date. Depending on the volume of special effects, the start date actually gives Disney the choice of Summer or Christmas depending on how the already crowded summer 2015 schedule shakes out. Other major releases include Superman vs Batman and Avengers 2.
I base this on the Transformers production schedules when principal photography starts about a year (early June) the year before) before its intended release date (late June), with post-production starting about 8 months before the intended release date (October). Considering that franchises' budget and special effects are in the same scope as Star Wars, then the extra 6 six months that the January start date is giving Star Wars should be more than enough breathing room for Disney to make an informed decision on the best release date to maximize their profits.