Ahem. I'd just like to say the following:
Spiderman gets bitten by a 
genetically modified spider?
		
		
	
	
Wait, he squirts his own web out of his wrist, rather than making it in the lab?
There's no Tom Bombadil? No Barrow Wights? 
Jar Jar? *gasp* Midichlorians?
Ok, I take that last one back. Midichlorians sucked, period. 
My point is: it's a movie. Don't over-think the 
origin of the plot, just go enjoy the movie as a movie. The first FF wasn't bad (sure, it wasn't Spiderman, but what can be?), and this one looks better. Who cares if they do a power-switcheroo? Is that somehow unrealistic? Like 
any superpower falls under the term "realistic".