I've noticed a lot of potentially useful effects that we can inflict on bosses never really work.

Is there ever going to be a viable alternative to a SCH with 9-second Stuns?

How about Beastmaster with fully merited Feral Howl and reduced recast timer?
How about Dancer Stun Flourishes?
How about Blue Mage terror spells?

Is there a way we can reliabily stun a delve boss without the need for a specific type of SCH?

Edit: I've kept my post brief so that as a community we can discuss possible variety in Stun mechanics.

Thank you.