I love the idea of the roll top, which seems to give a little more leeway in packing. I like my Osprey Savu, but at 4L it always seems a little tight, but it does hold my pump, tools, pockets are great for treats, and I have stuffed a gillet and tube into one of the bottle slots.
Hard part is moving my tools and supplies from bike to bike, I throw everything into the frame bag of my gravel bike, and pull them out again when I need a full pack for when you need a few litres of water on your back — plan is to design some sort of pack roll and sew it up just to make it a bit neater.
I do carry a chain breaker multi tool, every time I don’t is when I (or somebody else) needs it, of course if I have it I don’t need it.
And two pairs of gloves, cold weather + plus a lighter pair once your fingers warm up; long, long rides because it is so nice to put on dry gloves at the halfway point (somebody invent durable merino-lined gloves). Short rides one pair.
Completely forgot about my Leatherman, gotta’ be in one these pockets...next to all these zip ties.