Sorry but I find your question to be...umm...interesting. As you know cleats are not made to be walked on so whatever cleats you get there's going to be times when walking will be difficult. I hope you're not basing your pedals/cleats choice on ease of walking? I suspect not.
Like others have said get cleat covers to mostly protect the cleats from scuffing and scratches vs ease of walking. My speedplay cleat covers help me get around but only for a short distance (ie pitstops - convenience stores, etc...).
Actually, to me ease of walking is indeed an important factor. Walkability was actually one of the more important factors, given that any of the major pedals work fine. Th
From what I've seen, Shimano and Time among the major road pedal brands are most walkable. Not that you want to go for a walk, but to and from the house, car, and in and out of the Quickstop or restroom, they are safe and easy to walk in. Speedplay might be the worst in terms of clumsiness and the hassle of contamination - I've never had any problems with mud or dirt w/ my Shimano SPD-SL or Time RXS, fwiw.. But, that might not be all that important given their other unique features that some riders are looking for.
Oh, and since the OP did happen to mention weight of the cleat, if I'm not mistaken, the speedplay cleats are quite a bit heavier than others. The pedals themselves are, I think, the lightest though.