Strictly speaking 'no', but the process is defined to expedite inclusion of new features with the minimum headaches.
The maintainers are very busy. If you present a large feature with no design discussion, the maintainers are likely to ask you for an explanation of the design so that they can determine if your implementation matches the intent of the design.
The worse that can happen is that the feature that you spent considerable time developing is rejected for design reasons, or duplicated efforts or suitability reasons. The process provides checks to ensure that when you submit the feature is desired and designed/implemented in accordance to community guidelines.