Charge Rifle vs Havoc and Select Fire

Trying to understand what the thought process was behind creating the charge rifle, when we all know the Havoc with select fire is pretty dead and could have done with this buff.

Why didn't we just modify the Havoc's select fire to basically become the charge rifle? 

What we have now is essentially 3 energy snipers, 1 of which (the Havoc) is never used.