I wouldn't upgrade my pro to prem/le. The features aren't worth the extra money imo.
The crossbow mode on pro is fantastic and rewards accuracy and skillful flipper moves. The crossbow mode on prem/le takes away the flippers. Might as well turn crossbow into a video mode. I've also heard the Austin Powers cannon doesn't make all of the shots consistently? PF dimples are free.
Right now the Woodbury shot on pro is an extra ball or a crappy mode. Adding a drop in front of it and making it harder to get too is not helping me to want to go after this shot. Adding a spinner in that shot is a waste of a spinner too.
The ramp is the worst though. I've seen threads of people putting weather stripping under the ramp so it doesn't reject or mess up their playfield? Seems worth the extra money to me!
TWD is an awesome game though. Absolutely love it and I think when the code is complete it will be one of the best Sterns to date.