I've toyed around with this idea, and in my testing on various maps with friends, I believe that increasing the number of patches at the main and natural from 8 to 10 whilst decreasing the minerals per patch from 1500 to 900 improves game flow.
1) Bases take more workers to saturate.
2) Bases mine out a touch faster because you have more mining surface area, more workers AND slightly less base minerals.
This encourages players to expand both because they get an economic advantage in doing so, but also because bases tend to mine out faster.
In our testing we decided it was better to keep the number of patches at additional bases (i.e. 3rd, 4th, etc) at 8 to encourage further expanding as the game progresses.
I highly encourage players to try this out for themselves. It is easy to change any of the blizzard maps to have 10 patches at mains and naturals and then play a game with your friends online.
If that is too much work, test it out on "Orbital Station" on the NA server. Note, this a map I threw together in an afternoon when we were toying around with ideas regarding map size and macro dynamics. It is NOT a professional map and is NOT designed for competitive play. I thought I would post it here as a sort of "proof of concept" for those who are still intrigued by how map makers might change the metagame by trying to improve macro dynamics.