That the point. Is isn't that better to use frost bow for cc which have 30 sec cd, and after it can be dropped, waited CD, and picking another before its gone(which is more often than focus)?
I perceive "Arcane Power" more like "Starting Crank", but it's also shared with 5 allies, but I don't know numbers how much it would benefit. Like for eg in comparison with Assassin's Signet.
I did few testing's and:
Berserker+Schoolar gave as fallow (No boons):
Without Arcane Power: 11903
With Arcane Power: 14279
With Arcane Power(but instead Besrerk I put Valk): 14492
This numbers are sums of 2 spells: Burning Speed (Blast Only) + Fire Grab
This make my want to have Catalyst ult 😄