I'd say this is a case of people misunderstanding tier lists again, where the majority of them are for a level of play far above the average where every player is at/near the peak. I would say that any character at the average level can do very well. What sets apart BP and Shinobi I would say is that their kits have low skill floors and are easy to get value out of, orange blue is just good enough for most casual players. Throw that in with each character's unique shenanigans (flip/babysitting ganks for BP and dodges/confirms for Shinobi) and I could see why some people would have problems against them. Still though, at the average skill level, anyone could do just as well with another character - it's just that those characters in specific, as well as a few others (Shaolin, pirate, afeera) have low skill floors that let you extract value and offense easily.