One of the challenges to riding with front panniers is the resulting unweildness all that extra weight introduces into handling—especially at slow speeds. It's even worse when you are stopped and trying to keep the front wheel from crabbing as you dig around in your Ortliebs. Because of the added mass, the front wheel wants to sway to one side or the other, causing the bike to 'get away from you'. I've provided bystanders all over the world with laughs as they watched me try to contain my bike as I ran around in circles like a dog chasing his tail.
One sure fire solution is to hook the front wheel to the downtube with a strap, but that only works in stationary mode and it doesn't do anything for slow speed handling.
Back in the day, there used to be a gadget we called a flickstand. It was a neat little widget that would flip down and engage the wheel so that it wouldn't flop around. Though I couldn't locate one of those gems, I did find this device on line. I've used it on a couple of tours and it works wonders. It dampens handling at slow speeds and, though it doesn't entirely eliminate wheel crab while stopped, it does slow it down enough to make accessing the front bags a reasonable endeavor.