From the preview:
When we were planning the changes we were going to make in Shadowrun, Fifth Edition and we were thinking about what we wanted to do to magic, we decided that it did not need changes as extensive as the Matrix (see this post and this other post for info about those changes). The system essentially worked, and it was consistent with rules in the rest of the game, so a major overhaul did not seem to be in order. That’s not to say everything was perfect. There were some balancing issues we wanted to address (including adepts, which we discussed here), some flavor we wanted to put in, some new things to add.