I see what you mean; the healers/dps group will be between seeds and pillars to soak waves.
One issue with this is the fact that pillars may spawn all through the base/entrance line, not just in the corner. This being said, the reason we usually get them in the corners is that we have mostly ranged soakers who are closer to the bottom-right corner to soak. But it's still random :)
Now, let's assume we can force the pillars to spawn in the bottom-left corner with the same positioning/tactic that we use currently. In phase 2 (seeds phase) we would need to swap side with ranged and tanks to use this tactic. I like this idea and we should try it if we get a good chance to do so ;)