Alcohol in the form of wine or vodka, causes the tomatoes to release some flavors that are only alcohol-soluble - you won't get that flavor any other way.
Also, through experimentation, I figured out what makes Mandina's red gravy so rich and tasty. They cook it a loooong time. If you like that style cook it 4-6 hours on low and add a little sugar.
ETA: Also a lot of New Orleans Sicilian recipes call for frying the tomato paste for a while to caramelize the flavors.
This post was edited on 8/18 at 7:39 pm