re 8 vs 9, yes it is only 1 more, but your example of 8sp 11-32 and 9 sp 11-32 is one I am familiar with. In our household we have both and all I can say is that when you ride bikes that have closer ratios, you really get to like it.

the 8sp 11-32 has a 20% jump in there, between the 15t and 18t, which is a big jump. I rode a 8sp 11-28 for a long time and now have a 12-25 on that bike, with a 12-13-15-17-19-21-23-25 which has closer % between shifts, which is just so nice.
I realize that a 12-25 isnt much use while touring, unless its on a bike with a 42/32/22 which gives a 22 g.i. low, but really my point is that having closer jumps is always going to be attractive and has real world advantages, easier on the legs and knees, nice in headwinds or long drawn out climbs where sometimes you are too high, then too low.

I guess I look at increased speed in back as a real plus, and for me having closer ratios are a priority and a real world advantage for my legs when you have a bunch of extra weight on a bike in a touring situation.

As I've gotten older and more gearing nerdier, I'll prefer to have a smaller crankset, but which allows a tighter cassette for the vast majority of riding speeds, in the 15-25kph range--as this is where it will be easier on your legs and knees and you will be faster overall at the same time (but still having a crucial low gear inch that of course depends on your load and terrain you'll be in).

here are three charts of three bikes in our household with various gearing setups, specifically look at the percentage jump between shifts.