Sent my application of this morning. How would you that they don't take reference letters into account? Just because they merely state proof of extracurriculars is needed, doesn't imply that they wouldn't use letters of reference to determine how many points they award you for "extracurricular activities"
I know their scoring system, although how they convert grading scales is a bit opaque. There is no standard for converting foreign grading scales to the swiss system, and from what I heard from other people studying in Switzerland, swiss universities convert foreign systems more harshly than vice versa.
I speak German, so this isn't an issue for me personally. I think there is definitely some truth to the claims made in the 2014 MBF thread about the language issue for landing a job in Switzerland. I think one should also take into account, that St. Gallen itself is not exactly an international hub and student life in general will be a lot harder, if one doesn't speak German. Speaking french will help your chances if you want to land in Lausanne or Geneva, but the northern part of Switzerland, including St. Gallen, is german-dominant.