+1 - anything too tight across my kneecaps aggravates mine, too. I think, even without wearing tights, colder temperatures make the fascia tighten up. It feels that way to me, anyhow.

I've always ridden Look-style pedals (well, ever since clipless was invented ) and I have the Keo Classic now. I think the Elle pedals just have a lighter release? Classics are a pretty light release, and they're all adjustable.

I've never heard of the platform size contributing to knee pain. Foot pain, yeah.

I don't know much about two-bolt cleats, but I think some cleat/shoe combinations make it easier to rotate the cleats, where others only let you move it front to back? I might be completely wrong about that. Look cleats give you a fair amount of choice as to how to position them, which is important if you have funky knees.