I have used Sno Seal for waterproofing on all of my boots, including our Asolos. The last pair of Asolos I bought weren't the Gortex. I guess they were 535s. Anyway, I like them and just treat them with Sno Seal. No leaks, and it conditions the uppers nicely. I'm excited to learn that they can be resoled. That's what I'm doing next time. I just wish there was a reliable way to tell when the mid-sole is about the give up the ghost. I had a little bit of warning on my first pair of 520s, but it was a good thing I wasn't out on a long trip.
This grand show is eternal. It is always sunrise somewhere; the dew is never all dried at once; a shower is forever falling; vapor ever rising. Eternal sunrise, eternal sunset, eternal dawn and gloaming, on seas and continents and islands, each in its turn, as the round earth rolls. - John of the Mountains: The Unpublished Journals of John Muir, (1938), page 438.
I had two pairs of shoes over the years that developed that problem. One was a pair of hiking boots that probably I did not wear enough , usualy opting for the low cut type. (I cannot remember the brand) Another was a pair of Garmonts that I really liked and used a lot. I think they were about to expire anyway, not much thread left but in a short period of time the midsole just crumbled. I even tried to fix them with shoe goo or something like that but I just got another short hike out of them.
^ How about the waterproofing? My Asolos are the only boot I've owned in which the waterproofing hasn't gone poof within the first 6months. My soles have delaminated but the waterproofing is still perfect.
I have used Nikwax for waterproofing and have never had any issue with these boots. That's why I went the re-sole route.