Lol not to be so blunt but IFS is garbage. The who system is the weak point. From the multiple angles in the tierod, to the idler arm, to the weak tierod ends, to the CV's, to the horrible articulation which makes things even rougher. A locker doesnt put more stress on the front end it takes some off. The locker in the front stops a tire from spinning faster and suddenly slamming down and catching traction.
Seriously we cant drive through a mud puddle without 44's and the Paris Dakar, and Camel trophys are done with no bigger than 33's.
Other countrys feel differently about there setups

they dont all drive like us or in most conditions like us , we 4wheel for luxury they might for nessesity you would (adapt) drive differently with that notion.
The Toyota 86-95 is the best IFS on the planet. (H1 is tied with Toy)
What is the who system?
Yes SA is better but not always the cure all. (Portals are!!!)
The locker does add stress, 100% to each side under power, put a locker in the front turn this method is more commonly used than "the locker stops the tire from spinning and suddenly slaming down and catching traction" in an open diff torqe goes to the wheel with the LEAST amount of traction and this keeps it from spewing its guts when it gets traction suddenly.
If you never needed articulation you would opt for the better ground clearence. (sand, snow, mud, planes areas)
If you always needed articulation you would opt for the SA. (Rocks, ahh?, mountanis areas)
There will never be one 4wd system that works perfictly in any and all conditions, sorry the H1 will never be a SA, and an SA will never be a IS.