I endorse the summary idea. It will help me decide whether and how carefully to read your posts.

I would like to know what you think; depending on what it is, I may or may not be interested in the details of why you think it. For example, I'd rather not spend lots of time reading detailed arguments for a position I already find obvious, in a subject (like metaethics) that I have comparatively little interest in. On the other hand, if your position is something I find counterintuitive, then I may be interested in reading your arguments carefully, to see if I need to update my beliefs.

This is Less Wrong, and you have 5-digit karma. We're not going to ignore your arguments because your conclusion sounds silly.

Furthermore, you don't necessarily have to post the summary prominently, if you really don't want to. You could bury it in these comments right here, for example.