Darth vader vs 20 rebel soldiers, that would be amazing! Its hard not to be greedy now that we are going to be getting and have gotten a great star wars film but, i need to see vader in action. What are the odds we are getting a vader fight scene in rogue one?

Having Vader present, and no showing off, would be a waste.

Fairly high. Although he will probably be a lot like he was in the opening episode for Rebels Season 2. More of a boogeymen/can't-really-fight-him-and-hope-to-do-anything-but-make-him-look-awesome-because-your-attempts-are-so-pitiful.

I highly expect him to also kill at least one of the main characters.

Low.

And I don't think they should. They said it was a SW movie geared away from the Force- which is an awesome idea.

Force Choke at least

@joey_destroyer_of_worlds: i concur but maybe a 3 minute intro of darth vader out on the battlefield?

I hope he shows up in a big battle and just starts walking towards the main characters rag dolling people with the force for about 3 minutes.