The content types does not change often but the content type of a content is needed for a lots of operations in the UI. PlatformUI should have a cache system for such model to avoid loading again and again the same data.

A possible solution would be to introduced a global cache service (to handle others potential model that do not change often like Section for instance). This cache service could be responsible for loading the content type, keep it in memory somewhere and check regularly the validity of the cached copy.