Shuttle coasters: These are quite common, often taking the form of a boomerang (regular or inverted). Other well-known designs include shuttle loops, impulse coasters, and the Mr. Freeze twins. Since these coasters go both forward and backward by default, turning the train around has no effect on the ride experience except for a launch or spike. I will say that Superman: Escape from Krypton is better than the original Superman: The Escape, both due to the faster launch and looking straight down from 400 ft up. It's not a must ride attraction, but I'd wait close to an hour for it now while it used to not be worth it if the line was anything over 15 minutes. I have a feeling Mr. Freeze (which I rode in the original configuration) is probably similar in that the spike and launch are better but the rest of the ride isn't likely too different. For most other shuttle coasters, turning the train around probably wouldn't do much (other than doing everything in reverse first...which might cause the second part of the ride to be a letdown).
Coasters with backwards sections: This is any complete circuit coaster that goes backwards at some point during the ride (such as Revenge of the Mummy). I actually think this is a neat trick, since riders travel backward through a different section of track than they covered going forward. However, for rides like Full Throttle that just use it as a gimmick, it seems somewhat pointless (my opinion may change after riding it, however).
Coasters with backwards trains: If a ride originally ran the train backward, that's fine. Otherwise, turning the train around is a total gimmick. While running one side backward on racing coasters is somewhat neat (assuming the trains are racing), on a ride like Batman it seems like it would actually hurt the ride experience. When going backward, you cannot see what is coming and are unable to prepare yourself for sudden twists and turns, and you are also much more likely to suffer from motion sickness. I honestly wouldn't be surprised if Batman opens and within a month the train is turned forward again due to too many complaints of an unpleasant riding experience and/or excessive protein spills.
In short, I think a ride should run the way it was originally designed to be operated. I like going backwards on rides that are designed to do it, but if the ride wasn't ever designed for it and the park decides to flip the train around, it won't increase my interest in the attraction and may actually decrease it. Also, for me to consider a coaster a new credit, the track itself must change, not just the trains.
My local park is Six Flags Magic Mountain. When they flipped the cars around on Superman, it took a ride that had become mundane and boring and breathed new life into it. But that's a shuttle coaster and will always go backwards at some point. Every October, a special backwards train is added to Colossus for Fright Fest. Again, it adds a whole new dimension to the ride. Both of these rides are dual-track. I'd like to see the park dedicate each side of the track to running different directions year round. I think they'd get a lot of mileage out of that.
I really hope they decide to flip a train around on our Batman: The Ride. But if they do, I hope they also offer another train facing forward for the less intrepid.
Kurt Dahlin
The Coaster Guy
I prefer when the whole coaster is not backwards.... but maybe has a backwards section like Expedition Everest. Going backwards for the entire ride is kind of interesting once or twice, but it's not that fun going up a chain lift backwards. People generally like to see where they are going, which is why we don't like riding in cars backwards.
I enjoyed backward-facing roller coasters when I had the chance to ride them (with the exception of sit-down and inverted boomerangs.) One of the best times I ever had at a park was closing down Racer at KI backwards several years ago. So I voted "first in line" However, if GAdv runs Batman backwards, I would not count it as a new credit. I do count re-located coasters as new credits.