I don't think the diet is that restrictive....I eat lots of veggies, fish, chicken, some red meat, nuts, seeds, rice, quinoa, millet, beans, including sprouted beans, and maybe one apple or pear every day. Eggs would normally be included but I'm off them at the mo. I just restrict dairy, gluten, sugar, junk foot and try to avoid dried fruit.
I think if you were going to go vegan you'd have to make sure you had an excellent diet with lots of sprouted beans and grains, nuts and seeds, and obviously lots of veggies...maybe superfoods like spirulina.
I was vegan for a short while once but it didn't suit me as I found I really needed the animal protein to help with brain function. I found these proteins much easier to digest than say tofu or beans and grains.
Did you want to try it as you're vegetarian anyway for ethical reasons or you just thought a vegan diet would be better?
It's a very individual choice balancing ethical beliefs with what benefits your body....I hope you make the right choice for you :)