That's what XDA is for!
I'm not an experienced Android developer, but I do know that the Dual Shot, Slow/Fast Motion features are certainly possible to implement. It's purely software related.
This is just another way for Samsung to make the S4 Active seem like it is less capable, or else everyone would've got an S4 Active.
But that's what XDA is for, bringing out the best in our Android phones, by maximalizing the software!
+1 for Dual Shot and Slow/Fast Motion!