47 talents in three trees, 1 of them renamed or reworked since Classic.
From the Forever beta client's own talent tables (build 1.60.1.69977). Talents marked "was" have a new name compared with Classic Era, so their effect has probably changed too. The beta can still change any of this.
Starting priorities, based on how Classic stats work. Forever is still in beta and Blizzard is changing stats, so treat these as a starting point. The upgrade checker lets you change the weights.