I was at Universal Friday and Saturday this past week. It didn't open on time Friday but opened around 9:10 on Saturday. Both days had some downtime but from what I can tell it was running most of each day. The queue line stayed open until close both days and I was able to get three rides in. The queue line was fun but the actual pre-show was only running one of the three times I was in line. I truly enjoyed the ride itself. I wish the train moved a little slower in Hagrid's Hut and when we went past Fluffy since we seemed to move past very quickly, but the launches were great and the coaster portion was really fun. As someone else stated, the on board audio really helped make the ride. Overall I absolutely loved it.
If it was a significant enough impact to cause some damage to the chassis itself, it'll never be perfectly fixable. It's like if you get in a moderately serious car crash - you get your car fixed but now the seals won't fully seal or you have some electrical issues or you have other random little nuisances. If they already have two spares, they're likely just cutting their losses since one of the trains probably would have ended up as a spare parts cannibalization eventually.