Yesterday in Eskdale, it was lashing it down pretty much all day. We crossed streams that had become rivers, and rode trails and even roads flooded by overflown rivers and tarns. Several were knee deep. We all wore sealskinz. We all had wet feet.
I think anything capable of keeping feet dry in yesterday's situation would be something like a set of waders taped to the tops of thighs, and I doubt that would have been too nice on the climbs.
You're balancing the need to not boil in the bag and keep dry (impossible anyway cos of sweat) vs realistic protection. Sealskinz do fine up to a point. You can step in a stream and they'll stay dry, and they'll fight a certain amount of spray. Couple them with man tights over the top, goretex boots, and overshoes, and they'll withstand a lot more wet. But even then, once you've waded through your 5th torrent you'll have wet tootsies whatever you wear.
Personally, I find the combination of sealskinz and goretex boots good in as much as when they do get soaked, at least they stay warm – a bit like a wet suit, especially if you add a thin pair of merino sock liners.