Well we all know we'll get the regulars appearing, with most of them not suitable for in the ring action. Apart from Piper and the Outlaws, the majority of them simply offer nothing.
I want there to be an element of surprise, like announcing the first member of the Hall of Fame and for that person to actually be there. You could have The Shield in the ring and suddenly the original NWO appear or the jobbers that are 3MB getting a beating from Warrior.
Without this or a new wrestler from the past who can offer something, the Old School Raw is going to get repetitive and rather predictable.
I wouldn't actually mind seeing the title belts going retro for one night as well, certainly brings a change not done before.