After using a 4 oz. pair of neoprene dive sox with soles for several years, settled on a 5 oz. pair of Zems for camp shoes, partly because the Zem soles are stiffer and protect my feet better from rocks.
But the switch to Zems was mostly due to the realization that any flimsy booty is not suitable for many river and stream crossings. You need something well connected to the foot, and with a sole thick and cleaty enough to allow you to keep upright without pain as you go wading through deep water over sharp and unstable rocks (and maybe broken glass or metal) in a strong current.
The only thing I've seen on these threads that works, as a light alternative to hiking footwear, is a very light pair of running shoes. There was a post about a pair under 8 oz on one of the threads, but sorry, I forgot the name. Maybe one of the Asics.
I just don't want to carry the extra half pound or more, so do the crossings in my hiking shoes. BTW, even with the WPB liner, the hiking shoes dry quickly while hiking in the sunshine. It helps a lot to swab them out and change sox after the crossing, but pointless if there are a lot of crossings.
If I were going to hike in temperatures at or below freezing, I would definitely carry the extra weight of the running shoes to keep my primary footwear dry and warm.
"Lord, I waded through deep water, tryin' to get home." - The late Rev. Gary Davis