It's funny how different a lot of the details are - depending on the kind of trip that you're doing. For example, I did a quick overnighter this weekend from BCC to LCC via Lake Blanche and Mt Superior - weight and bulk was of the essence since the hike involved scrambling up the north side of Superior.
As a result - I didn't bring a bug net or water filter - I knew there wouldn't be bugs up there anymore, and above Lake Blanche, I'm comfortable with dip n' sip, given the lack of human and animal activity. However a lightweight bivvy was a good touch, as I wanted to cowboy camp without having dew soak my bag (plus it'd likely be below freezing and the bivy adds a bit of extra warmth. A poncho-tarp would do the trick, as the forecast was beautiful. And for a setup that light, I could get away with a frameless pack very comfortably.
That being said, that setup wouldn't work at all two months ago, as the bugs would be horrendous. And it won't work next month, because I'll need a warmer bag to deal with chilly October nights. I'm curious to hear about the trip that you took this setup for - where was it and when, and what climate conditions did you expect to face?