fleshbroiler said:"Best" is pretty subjective, but all of your criteria are easily met by Speedplays, except the wide pedal bit. Seems a wide pedal might be a problem when cornering though. I think a more important factor is contact area between the pedal and cleat. This is discussed at length on their website.
I have a pair of zeros and I love them. I hated replacing the cleats for my Looks so frequently. I use coffee shop caps now and my cleats look pretty fresh for being 18 month old.
Ultimately, most good quality cleats wil give you what you're looking for. The 4 other guys I ride with all use different pedals and love what they use.
+1 for speedplay zeroes, but agree all the top-quality systems work fine.
1. Distributed support via the wide, flat 4-screw cleat. Besides, support is a function of the shoe sole, not the pedal size.
2. Mine are holding up fine at 16K miles. Just lube every 1-2K miles with a mini-greasegun. Bearings may be small, but they hold up great.
3. Zero cleats have al on the bottom, not plastic. Use Coffee Shop covers for walking, and they will stay clean and last a long time. I'm on my second pair of cleats now; first lasted 10K miles. Used to go through Look cleats twice a season.
4. Wear is never a problem; but you must keep the speedplay cleats clean since you're walking on the moving part.
5. Zeros have a wide range free-float that is adjustable (on the cleat).
6. Have never pulled out of the Zeros, even on my track bike yanking hard.