Too bad about the Xiongda. I always wanted to try one of those. It sounded like a neat idea, but I was never sure about reliability and they essentially disappeared from the market, anyway.
Failure on a front motor:
You build smart, not stupid. So you never use an alloy fork. You certainly never use carbon fiber and you do use steel, which the OP has. To get around bending, you use a substantial steel fork. Not for example a road bike unless you are putting on a 250w motor and a small EU-spec controller. I looked at the fork and it is substantial, with steel dropouts with fender eyelets. The fender eyelets are ready-made for torque arms.
What can go wrong? Well, precious little so long as you are not an imbecile and put on something like a powerful front motor... say, a QS203v3 and tie a 60+a controller and 72v battery to it. Beyond that... failure is not going to happen so long as the builder isn't stupid, and takes the precautions of dual torque arms and substantial steel forks. I have 7500 miles on a Surly Ice Cream Truck fork and 35a G060 Bafang fat motor. Also I think 3500 miles on one short 20" steel fork with a 25a G020. and just over a thousand miles on another identical bike/motor/fork. These last two are cargo bikes and while those motors are less powerful at 45Nm, they do much heavier duty than the 80 Nm G060. Oh and another 2500 miles on my sand crawler. Thats another 80 Nm/35a G060, which uses an Ice Cream Truck fork now, and used to use an alloy Origin8 fork for about 2000 miles (did that one only because the dropouts were positively massive, and I was running on the street mostly. When I switched to sand and beaches, I went to steel).
The front motor failures you see - and there are plenty of them - occur with dumbasses who used suspension forks. If I had a dollar for every alloy suspension fork whose dropouts sheared clean off thanks to a big DD hub motor (with or without torque arms), I'd have my bar tab paid off. Noteworthy is I have seen more than one of those where the torque arms held the fork together for the ride home despite the sheared dropouts. Otherwise its going to be a faceplant and injuries. I have never seen a failure leading to a crash with a steel fork and dropouts. I have seen steel dropouts spread, but that is always due to a lack of torque arms. Count me as a dumbass on that one as on my very first ride on my very first build after a long day of assembly I forgot to tighten the arms. No crash, but forks ruined forever. A mistake I never made again
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On the fear of front motors:
If you go to Europe, particularly The Netherlands, where there may be more bicyclists in one town than there are in the entire United States, you will find low power front hub motors (like the kind most of us are discussing for the OP) are plentiful, with no whimpering or hand-wringing.
Go here and just scroll down. Bikes 7, 8, 9, 10, 11 and 12 are all typical front motor city bikes and while they look awful to us snobby Americans, this is what you see on the road in a cycling society where people park on the street and don't try to impress others with them (these are actually very spiffy compared to most bikes, which usually look like
rolling pieces of junk).
See this? That is the Central bus terminal in Amsterdam. Train station is next door. See what looks like a grove of bushy trees over in the lower right? Thats
part of a bike parking lot for daily commuters. There must be 1,000 bikes parked there. I made that number up but still its a lot.
You see more daily cycling and ebiking experience in that one picture than is ever going to show up on an internet forum.
