Just an IDEA....What do you think?

I was doing some research the other day, going through a bunch of other people's Blogs, when I came upon this IDEA. I have not seen it used anywhere, and don't know if there is a reason for it or not. I am interested in hearing your comments on what you think of this IDEA, and if it has any benefit with Google, or just visitors to the site. So here goes:
Every Blog I go to is a rolling Blog. Meaning the most resent blog is on top of all of the others. Even if the Blogger has narrowed his niches down, the blog still covers a number of micro niches with in the main niches.
The indexing is also the same, you can scroll down and see what has been written. Most of the time on the right side of the page you will find an index by the month, or past years, if the blog is old enough.
My niche is very wide, and has a lot of sub- niches. The niche is Organic Gardening, but that includes, Vegetables, Fruit, Flowers, Lawns, and a number of others.
OK, Bob so what is your IDEA, already!!! Well here it is, no more waiting.
What I am thinking about is this, when someone clicks on the Blog tab in the navigation on my site, it will have sub- niches listed. This way if the visitor is interested in reading about vegetables, they click on that sub-page, and it brings up a page listing all of the posts titles I have written on that subject, and hyperlinked to that post.
I know this would create extra work for me, but it would make it much easier for the visitor to find the information that they are looking for. It would also make their experience on the site more enjoyable, and maybe stay on the site longer, which I know would help in the ranking.
I would be very grateful for any feedback on this, or any other IDEAS that would also help with using this IDEA to boost Google ranking.
Thanks for your time,
Bob