It sounds like you don't have a clear voice. To find that you might want to try defining clear goals for your blog and limiting it to a certain topic area and

It sounds like you don't have a clear voice. To find that you might want to try defining clear goals for your blog and limiting it to a certain topic area and then begin to write. By reposting comments there's no overarching thread that pulls your blog together into a coherent narrative. A good blog does that. It seems like you're able to write well and have the time to do it so go for it. PS It might help to find a comment you liked and then re-write it into a blog post, IE explain to your audience the context and then your opinion/thoughts.