There needs to be some kind of synergy between the two alliance legends. It seems odd that there is no incentive to chain the separate ability sets in a meaningful way. Two ideas off the top my head:
The Luxon abilities already produce self-might and quickness, why not allow you to share that via Awakening (a Kurzick ability), perhaps add a self-buff damage modifier which scales with the number of allies affected to benefit DPS specs using the ability as well. Reaver's Rage could then function as a CC ability which also grants stability to nearby allies. Obviously, the stun-break aspect would have to be removed from both.
I'm not too keen on the Urn ability, but if such an ability exists why not make it so that Luxon abilities deal increased damage while low on health? That way the Urn could at least serve as a reliable way to trigger extra damage. Archemorus's spear could perhaps grant self-alacrity or quickness so that it can be shared via Awakening if changed as mentioned before.
