Of art, artisitic concept and its expression

As I glanced through the Art-Works at Esplanade today, a thought struck me. As most would agree, the essence of an art-work lies in its two aspects - the concept aka idea and the technique aka execution. Have you ever wondered which one, if at all, is more significant that the other? I believe without either, an art-work would not be as valuable and worse - it would not exist at all.
An idea in a thinker’s mind is intangible and shapeless. An idea that is not communicated is almost as if it did not exist at all. It’s like a soul without body. It needs to be conveyed to be appreciated as an artistic expression. On the other hand, a technique without an idea is direction-less. One cannot demonstrate a technique without an idea or at least an imitation of an idea. In my opinion, it is the fusion of concept and technique that defines an artistic expression.
Further to this discussion, how easy it is to for an artist to be equally adept at both conceptualisation and actualisation? Consider the case where the artist is both the idea-man and the delivery-man. In order to be fair to the art-work, the artist must be proficient in both of these skills. To conceive an idea as novel as it could be and to execute it with an equal precision may be difficult. In that case, will it be a better idea to separate these two task and let them be performed by a pair of specialist as opposed to a single generalist?
Specialisation of task may solve the problem when an artist is not equally talented at both idea and delivery. For the purpose of an example, let us examine the case of a theatre production. While the director who conceptualises the act, it is the actor who executes it. While the director decides what emotions must be incited in the audience, it is the actor who invokes them through his acting. Both specialise in their own domain. In this case, the channel between the idea and the delivery becomes critical. It is important for the actor to be at the same page with regards to the understanding of the concept. Similarly its important that the director is successful in communicating the exact concept to the actor. If not, they will not be doing justice to the art-form.