Like you, I enjoy the comfort of Merrell shoes and the uppers seem to be very well made. But the soles seem unusually fragile and wear quickly. I ride mostly with Stolen Bike Thermalite pedals, which aren't too abrasive, so hopefully the Merrell soles will last awhile. They aren't falling apart, shredding or cracking, just wearing down quickly from normal riding and walking.
Too bad because they're very comfortable and the reflective panels really light up at night.
By far the most comfortable shoes I've tried so far for platform pedals and walking are Five Ten Freeriders. They fit me perfectly, which is unusual. I have very narrow feet, an A or AA width, and usually wear size 11. So I'm basically shopping for ice skates. With most shoes I have to settle for a B or medium and get creative with the lacing to ensure they fit right. But the Five Tens felt perfect.
I was skeptical so I tried some Pearl Izumi shoes too, their line of trail running shoes which were described as having stiff enough soles to be good for platform pedals as well as trail running/hiking. They were comfy, but the Five Tens felt better.
Anyway, I did all that footwear testing just before the holidays and need to get back to the store and buy a pair of the Five Tens.