Not to butt in here, but sampling is just a way of saying they have equally good processors. It so happens that the features you talk about, give the g2 a definite advantage over the g1. The g2 will give you more parameters to tweak with more knobs, and this potentially gives you a better sound. This is because the better sound is the sound you hear in your head, and you have more controls to tweak to that tone.
The g1, however, would be better for people who enjoy its easy-to-use controls. Minsan ayoko rin yung tweak nang tweak. But potentially, the tones you get out of a g2 will be better than a g1.
Pero people, compare nyo rin yung online manuals ng zoom. Case in point, walang intelligent pitch shifter yung g1, fixed intervals lang like 4ths or 5ths. Because the g2 has more controls, you could have major or minor 3rds, major or minor 7ths, depending on the key you set it.
A g2 will kick a g1's butt everytime.