You wrote that:
" Resounding Challenge
6 targets; 10m range
 Call to Battle
2T Threat every 4s for 16s
6 targets; 10m range"
The range of those gambits is 25m (or afaik even more with proper legacy - can't check it now, btw the possibility of lengthening the range would be worth mentioning), and 10m is the radius from the initial target.
That's quite important, as Call to Battle, giving as much raw threat as EoB is a great tool to grab mobs from a longer range, especially in chaotic situations that quite often happen in PUG skirm raids.
Warden(85), Minstrel(85), Rune-Keeper(85), Burglar(85), Captain(85), Hunter(85)