Most of the used supportive abilities are capped on a 600 range (e.g. Banners, Retreat, Call of the Wild, For Greater justice, Save yourselves, Spotter, EA…) and combo finisher have even a lower range of effect. It is by far enough if you stack in a corner, but as soon as you spread out a bit this starts to loose effectivity.
My idea is to leave the range for non party members as it is (I guess this makes it easier to detect targets) , but to increase the range of skills and combos for members of your party to 1500 or even more . This makes it similar to the GW1 system where Group-affecting Skills had compass range.