.... I am sort of the opinion that if there is a problem with the splines that it must be from either back lash (I call it slop) in the splines or too soft of metals being used,... ...
Well, it has more to do with size...and heat.
The splines are just plain small..and have to handle all the torque/power the engine puts out. They also get hot, hence the use of high temp grease..(not high pressure grease, diffrent animal really) Moly ,as mentioned, sticks well and is resistant to "melting off".
Even Moly grease will , over time , "melt off" but as this area is not easy to get to, and tends to only be opened up and checked when you are changing tires, Moly is one of the few that seems to last in there.
The more expensive, but "better" alternative is DuPont Krytox synthetic grease. This is what the high dollar racers and NASA uses to grease things they know will get hot.
Most shops do not even know about using Moly grease in there, and this is why we do not take bikes to shops but work on them ourselves......