UML completeness and complexity

So often I've heard IT people talking about their difficulty in using UML. The reason for this spread “feeling” maybe lays the fact the UML is now a very large set of conceptual tools, and it is still growing. Personally I understand and appreciate the great value of the work OMG's people is doing to complete UML, toward an actual Unified set of modelling elements; I think the community needs such formalised concepts. Nevertheless I see that for a lot of people is very difficult to approach analysis and design with UML: which diagram is more appropriate, from which point of view should this matter be modelled, which is the exact meaning of this set of elements, are all questions that can reduce the confidence in UML. I believe – and this is an opinion not a matter of fact – that a meaningful reduced set of UML could be a more aggressive proposal to push on UML in the IT community. What I'm thinking about is a subset of the whole UML from which would be possible to obtain the models we need, less diagrams but well known, widely used and completely understood. Finally, we could aim at very valuable objective, a completely computable UML. Currently many efforts are carried on to define specialised subsets of UML to fit the needs of particular fields of application, but this is not what I'm thinking about, I'd like to have a pervasive Unified Modelling Language and not many specialised Disjoint Modelling Languages.