My old leather B1's were perfect, until I struggled to find a modern crampon to fit them, so felt I had to modernise to get a stiffer boot to fit 12 point crampons which were required for altitude climbing in the Alps.
I bought a pair of Mammut B2 gore-tex boots with the Crampon "lip" on the front and back, and they have been adequately waterproof when out and about in Scotland and cannot grumble so far,
However I do fondly remember plastering the snowsneal on my old leather boots, blasting them with a hot hair dryer to get the bees wax to melt right into the leather and then applying another coating of snowseal to make sure.
Never had an issue with lack of waterproofing, so modern isn't always best.