The issues with low spoke count are thus:

1. A bad build will allow wheel to get very out of true.
2. A Weak rim can fail easier as it has less support
3. If a spoke snaps wheel will become significantly out of true

So you have to weigh up the pros and cons. A good build will solve one, not buying rubbish will slove another, the final one… well, how lucky do you feel?

Finding a beefy 28h rim will be your biggest difficulty I should think. If you could get something like a Mavic A719 in 28h I'd certainly give it a try. The biggest things influencing my decision would be where/how far I was going. A bit of UK based touring with a light/moderate load, why not try it. Heading off around the world, maybe look for something else.

My Bontrager Race-Lites are 28 spoke and are surviving all the jeycore xc stuff this 16 stone racing snake can inflict on them….

Ive got a pair of extralight (italian) rims that run 28 spokes, the rims arnt amazingly light (450g) but they seem pretty sturdy. Both extralight hubs have now failed (afteral, they are Italian) and ive rebuit the rear onto a 28h Hope Pro2, since then ive never had any bother with it at all, i think the stiffness in the rim and tight build have helped. The front wheel failed when the hub flange went pop, leaving 2 spokes on one side not connected, this left the wheel with a fair sized buckle, but again due to the stiffness of this particular rim it wasnt bad enough that i couldnt ride it home (its a disc wheel too).

To contrast that, i replaced the front wheel with a hope-hoop/dt combo (32h) which turned into a giant wobbly pringle on its first crash (i fell out the van when wheeling the bike out, hilarious for everyone but me who was left with no front wheel). So in my experience.. 28h good, DT rim bad.

I suppose another way to look at it is that all the 'oldies' still baulk at the idea of using 32h for anything other than 'racing raod bikes' when clearly technology has leaped way beyond the 36h for anything other than heavy touring/tandem riding. Also worth noting, mavic dee-max wheelsets have been 28 spoke for a few years, and you dont see many of them buckled (just destroyed from rocks).

If you'll ignore the hyperbole…. the 4 less spokes are but pissing in the wind compared to bending each side of the rear triangle in by 12.5mm(!). Spacers and/or a longer axles are surely the way forward here, but even then it's not ideal.

Flog the hub and buy something proper for the job!