I'll second @circuitmonkey! I love my Astrals for portaging, I've got both the Lowyak and the Brewess and have been really impressed. I use the Lowyaks more for daytripping and if I'm portaging it's my kayak around a rapid I don't want to run. The Brewess are defintely more of the workhorse. I used to be a canoe guide in northern Michigan and wore grippy trail running shoes that dried fast as my portaging shoes back then, so I've always prefered a lighter weight and breathable option.
I did guide a short fishing trip once where we portaged in wading boots and it was pretty clunky, but that could be my personal preference. Plus, it wasn't the foot deep muckiness you mentioned, so we weren't really getting the benefit of avoid moose muck!