dws, I've lived and traveled in Latin America, so I get the steep thing, but about torque and all that, it really must be down to your weight and the power you put out when going up steep stuff.
I weigh less than half of you, and while I've had 50+ lbs on my bike going up steep stuff, I know even at my lowest gear , 22 small crank and 34t cassette, there's just no way I can be over burdening the drivetrain just because I don't have the force you do. (And the force needed to get you up the hills, so much less for me so I can spin easier with higher cadence, so less torque actually going into chain etc etc)
what crankset is on your bike, mine is a mountain bike triple.
is mud etc a factor with your freehubs, ie a lot of dirt getting in etc?
I also use a mountain triple, but I customized it to 48-36-22t. Couple that to a 11-40t 8s cassette and I can climb loaded without standing on the pedals at the low 22/40 ratio on a 26", about 1,14m per revolution and 5km/h (about 3mi/h) at 75RPM or 4km/h at 60RPM on longer climbs, almost too low to keep balance, but easier on my legs, heart and lungs.
The high gear at 48/11 makes 9,00m per revolution and I can keep a comfortable cruise speed of 25km/h (15mi/h) at 45RPM on perfectly smooth flat tarmac, as long as the wind isn't against me. If the world isn't perfect, I usually ride on 48/13 or 48/15 and rise the cadence to compensate, but that costs endurance. I tend to plan my rides about 100km/60mi max per day.
Mud isn't a factor, really. I almost never ride when it's rainy on dirt roads, except when strictly necessary. My rides consist of moving around town (tarmac and stone paved roads of varying conditions, wet or dry climate, sometimes very badly maintained, but still a road) and intercity rides on secondary roads (dirt and gravel roads are the rule, almost 100% of times dry climate).
The RM30-8 I've used for 9500km simply doesn't have any contact seals, relying on grease alone to prevent water and dirt intake. I repacked it every 3000km, giving it a thorough cleaning with a rag and degreaser (not a lot, as I couldn't open the freehub body and it could remove it's grease if it's soaked), replacing dull looking bearings, checking cones and cups for pitting (replaced the cones once, but the cups where OK) and packing as most lithium water-resistant grease I could.
I know lithium grease is bad for plastics and rubber seals, but the RM30-8 simply doesn't have any parts from these materials. With both the M430s I couldn't even get to overhaul them, as their freehub bodies seized before I could reach maintenance time, but I bought some Shimano internal hub grease for it (the yellowish white stuff, not the green one).
That basically sums up my maintenance routine of my hubs and headset, and I don't see anything wrong with it, correct me if needed.