Moto X is a flagship phone. While Moto G is mid range or you can say a poor man Nexus.
No doubt X is better in many aspects though G has better battery life than X, further G has some pros which gives it slightly edge on X.
Both phones are targeted for a better user experience not for insane specs.
I just wish Moto G had 4.7" screen.
Now Motorola is going on right path.
I have seen people's moving from their flagship phones to Moto G and they are impressed by what Moto G can't do which a flagship do.
Do you know Moto G has water nano repellent coating too 
Sent from my Moto G