I've now done 7K on mine, the large majority of that off-road.
I perservered with the air shock and I am now completely used to it and it is at a higher than average inflation (cos I'm lardy). I never thought I would get used to it but gradual inflation over 2 years worked for me.
The only time it is ever an issue is on the type of extreme downhills such as one we did in France the other week. It was so steep that you couldn't hold the bike still anyway, it was moving under it's own weight, my balls were on the tank and the rear shock wasn't helping!
We rode *lots* of slippy stuff including some very narrow hunting tracks, 2 feet wide. The bike is so competent that even someone like me with just a few years experience could consciously drift the whole bike sideways, a first for me, and not break my neck.
I still fell of at other times though (see pic).
So don't rush to change those shocks, it is rideable at lower pressures, you might look a bit Easy Rider but unless you're going mental it won't matter.