I don't see what the point is of opening the valve half
way to reduce water flow is. For most of the water use,
the washer is going to fill up to the set fill level whether
it takes 3 mins or 30 mins. The only time a half open
valve would make a difference is during the beginning
of the rinse cycle, when it spins and sprays fresh water
before filling for the rinse cycle. That is to get rid of any
foam and displace the water in the clothes with clean
water. So, I'd want the water to be coming in fast,
not slow. It doesn't amount to much water, its only
a few intermittent sprays.
The only time I've fooled around with the valves was
years ago when I had washers that did not auto-adjust
the temperature. Then I would adjust the hot water side
to make the "warm" temp right. Also, the above applies
to most toploaders. Front loaders are a whole different
animal with no reason I can see to screw with the valves.
But does having the valve half open have anything to
do with the failure? Probably not.