I feel like I always doom here, but I don't think this is a good direction. Class identity has been a sticking point for ZOS for years and years. Hybridization has killed a good but of that, but comp still demanded some differences in classes. With 2 separate available skill lines, you basically wipe the class completely.
This isn't terrible for PvE, given you just run meta stuff and don't necessarily care about thematic builds and diversity within the game, but the expectation of "run meta stuff" is only growing more and more.
PvP...it's going to either be amazing or absolutely terrible. Perma tanks already exist, and will only get worse with access to other class skill lines. Burst damage would go up, ball groups are going to be absolutely insane, heals will go up. Lots and lots of balancing needs to happen, and ZOS has historically struggled with this.