This thread is supposed to be about the anemic Mk 108.
The MK 108 is far from being anemic. What happened to you is the result of several factors, all of them not rooting in the cannon used but resulting from other issues, for example how the credit for kills is being awarded.
That being said, the Mk 108 is one of the most potent cannons in game, only other 37mm guns have a similar one hit - one kill capability.
In current year, almost 50% of my fighter kills have been made with MK 108 equipped rides - ~3500 out of ~7400 kills in. Not more than 4-5 enemy fighters have been able to fly after a single MK 108 hit by me, all hits to the engine. That's a pretty low percentage for an anemic cannon
