Please keep Mapbox GL JS open source. As you know, your library is very popular by the open source community for viewing web maps. Withdrawing its BSD license effectively means that it cannot be used as open source software anymore. Foremost, your pricing model means that it can incur huge costs for projects with small (or no) budgets, but which are used a lot

Your most recent move, i.e. withdrawing the open source license starting with v2.0.0, is a huge slap in the face for the thousands of persons who have invested a lot in vector tile technology. While you haven't received immediate financial benefits from all of its users (and, admittedly, that includes myself), you have gained a lot of goodwill. But with this move, you have thrown all that goodwill very quickly. It would have been much wiser to think of alternatives for supporting the development of Mapbox GL JS, like donations.

This brings me to the second point. For the development of a healthy open source community around Mapbox GL JS, vector tiles, and other technologies it is better not to keep all power regarding these technologies in one place, but to think of a better and more future proof way for governance. For example you can set up an independent steering committee, like the OpenStreetMap Foundation is for OSM.