But why do we need that? How would that be beneficial to mage gameplay? You're just giving an extra bar to look at and maybe forcing us to use phantom darts more oftne just for the sake of using TP.
Remove physical attacks like darts to obtain TP. So darts spams solved, no need engage.

Dont seems too complex to me to attain some TP before use X special spell. Melees have to attack from sides, behind, tank to face mobs around, check on links or pops and voke them too changing targets, etc. And for mages is too complex to use TP?

What mages win with this? Versatility not only see mana and cast.