the talk of lower than 19" is tricky for me because I know that with 4 panniers, tent etc I would need lower. The lowest geared bike I've had is 19.5 g.i. and I see going to 18gi. might be enough, but it really does depend on the terrain. When you start getting into places with the 20 and 25% stuff, I can completely see needing lower.

I find myself wanting to have a tight a cassette as possible, but being realistic that depending on where you go, you might have to just give that up for a 11-32 or 34.

I figure that if its really rare that you will hit super steep stuff, then its worth having nicer closer jumps that you will be using and appreciating for a good percentage of your riding.
If you are dealing with the bonkers gradients and or high altitude that saps your oomph, then you just are going to have to compromise.

as for the speeds and gears we tend to use for a big majority of time, I know that on my mtn bike, with a load, the 32 mid ring has me in the 19-17-15-13-12 cogs a lot of the time, covering the 15-30kph range, which is realistically where we are riding for the majority of the time.

With 26" 1.5 tires, these are the gear inch ranges I am in a lot,
moving to a 34 chainring more or less bumps me up a gears worth, which would be nice, compared is the 34 chainring with a 9 speed 11-32

32/19= 42 g.i 34/18= 47 g.i
32/17= 46.8 g.i. 34/16= 52.8 g.i
32/15= 53 g.i 34/14= 60.4 g.i
32/13= 61 g.i 34/12= 70.5 g.i
32/12= 66 g.i 34/11= 78 g.i

moving to a 34 chainring more or less bumps me up a gears worth, which would be nice, compared is the 34 chainring with a 9 speed 11-32

I have never actually measured the Q factor distance on my bikes, one with a road triple and the other with an older mtn triple. I don't feel theres an issue for me with the wider.