I strongly agree with OP. Having range circles/cones displayed is something that I've wanted ever since Beta of 1.0. However, it never came.
As it was mentioned before, for instant skills/spells, simply hovering over the skill icon should display the range circle/cone.
As for hardcore players that "dislike being spoon-fed", simply turn it off in the config menu as it would need to be a client-side visual aid.
One more thing, the spells and skills, as it was mentioned, should definitely be displayed as wide half-spheres like we see in the videos. A simply copy-paste of the individual animation in front of everyone is probably the lamest AoE skill/spell effect I've ever seen. Especially in an MMO, visual is extremely important this should be part of it.
The devs are doing a great job and I hope Yoshi-P & cie have thought of it already and it is in motion of becoming reality. ^^