If you keep to the main tracks you might get by in boots, but you'll posthole at some point for sure. I actually removed snowshoes for particularly steep sections when going down, as snowshoes become almost like skis, so it's easier to make your own steps by going heel first. But, for the most part I was wearing snowshoes. It really depends on how well packed is the trail: if you go after a snowstorm, it's going to be very difficult to go around with no snowshoes. I think most people were using snowshoes or skis to get up this past weekend. Some skiers were climbing steep sections in their boots though.

I don't think microspikes would have been useful. It was mostly fresh or packed snow. Even on steep sections, there were steps from other hikers that you can use, or you can make your own.