Reyna can look awful unless the following two conditions are satisfied:
- The player is competent with Reyna
- The team Reyna is on is competent
Reyna herself is not going to dominate a match, and a good Reyna cannot turn around a bad team by herself, but a good Reyna on a good team is amazing. She is the best support hero, bar none. Miko, Alani, Ambra, etc., are not in the same league because not only can Reyna shield and heal her team, she can increase damage on targets and slow them, melt their shields, and throw up a shield dome of her own.
However, a bad Reyna, or an inexperienced one, will be awful. You can get by as a bad Oscar Mike by firing napalm grenades all over and get lucky, but Reyna requires finesse. Personally, I am not good with her, but I want to get good with her because having played with a few who are I have seen what she can do and I want in. 

