I am currently using the Topeak system for my commute and I love it.

As far as your 'heel kick' worries I really only hit the panniers if I adjust my footing mid-rotation or if I have them stuffed to the point of breaking.

To help the situation you can hook the panniers to the rear 'fork' of the rack to keep them from possibly sliding forward. You'll see what I'm talking about when you receive your order.