aircraft

The chin turret affected speed of Gs, but were those two MGs worth it?

Interesting question you bring up: The frontal attacks were a big problem until the nose of the B-17s and B-24s got improved firepower via turreted gun emplacements. Interestingly, I have not seen much evidence that the pair of cheek guns on the B-17s were ever deleted. However, the cheek guns on the B-24s did disappear as turrets were introduced.

17's bomb capacity would have greatly improved if they never had sooooooo many MG's

When the Mossie being far faster could carry a heavier payload and it was SMALLER

The B17 exchanged bomb carrying capacity for being able to fly significantly higher than the likes of the Lancaster or Halifax and being considerably tougher - B17's could come home with damage that would have seen the crew of a Lancaster dead or in a POW camp. The result was considerably lower loss rates than those seen by the RAF heavy bombers.

The Canadian Lancaster squadrons that kept their belly turrets also had lower losses than the rest of the RAF which appears to be related as it made it easier to drive off Luftwaffe night fighters.