I was going to say, for mountain biking and hill climbing get a crank drive bike. If you did need a stronger rear wheel then putting a stronger rear wheel on a crank drive is far easier than a rear hub powered bike.
I have a hardtail Yamaha PU powered Haibike that also climbs like a goat, and I weigh around 105kg and carry 5kg in rear panniers and charge around off road to work.
I had a mavic rimmed rear wheel built for me that copes with the punishment. I am just approaching 9000 miles and have just entered my fourth year of ownership.
If you really wanted to reduce rear wheel punishment further you might consider a Full Suspension crank drive.