In her first day as a Wonderbolt, Rainbow Dash makes a bad impression, forgetting the essential rule of looking both ways when crossing the runway and crashing into a trash can. Because of this, the Wonderbolts saddle her with the nickname "Rainbow Crash," the same nickname used to bully her in high school. Upset by her new nickname, Rainbow seeks to find some way to change it. There's a lot of potential in that premise, especially given Rainbow Dash's tendency to boast in order to hide her insecurity. That trait especially comes through here, where Rainbow projects greater arrogance than she has in a very long time while also trying to hide her own anxieties. This is a potentially compelling character trait that very little is done with, and despite a consistently decent take on this dichotomy, very little is done with it, and it feels more than a little overdone for the level of growth Rainbow ought to have experienced by now.
Far more controversial is the Wonderbolts' actions, which were clearly inspired by the hazing prevalent in the military and in sports teams. Considering that the Wonderbolts are a physical performance team with a military background, this only makes sense to me, and the hazing in question doesn't extend beyond an unflattering nickname. The problem is, this nickname is associated with childhood bullying for Rainbow Dash, which is a potentially interesting concept that is dropped immediately after it was brought up. If nothing else, the conflict might have transpired differently if Rainbow had brought up how much that name bothered her, but most of the episode plays out like she's merely embarrassed by it. It's likely that new writer intended Rainbow's arc here to involve reclaiming the name, but it so, that doesn't come across very strongly given that the vast majority of the episode features her desperately trying to fix it.
The primary reason that I don't think "Newbie Dash" condones bullying is the framing of Rainbow's anxiety, which, excepting the brief moment that her history with the nickname was brought up, is mostly viewed as her worrying that the Wonderbolts didn't respect her. Despite the occasional hint to something else, the episode is primarily about acceptance and the different forms that it takes. In the end, the Wonderbolts don't defend their hazing against Rainbow Dash calling them out on it, but assure her that the nickname doesn't mean that they don't respect her and that she doesn't deserve to be there. It's unfortunate that, in execution, this is muddled by a variety of factors, most notably the lengths Rainbow goes to in order to change the name, which muddles her motivations considerably.
Indeed, the biggest issue with "Newbie Dash" isn't its implications but its wasted potential, especially with regards to Rainbow Dash. In theory, an episode about Rainbow Dash needing to adjust to life as a Wonderbolt is a great one, but where it should have been a character showcase for Rainbow Dash's strengths as well as her insecurities, it's barely competent in displaying her insecurities and how she overcompensates for them. Not much is made of this overcompensation, and the extent to which she does so feels regressive for the character, even if we consider that this is both a uniquely stressful and uniquely flattering situation for her. The idea of her embarrassing nickname in the Wonderbolts being the same as the one used to bully her as a child is woefully underdeveloped, and it might have been nice if the episode had addressed that the nickname could be potentially hurtful.
A lot of time is wasted uncomfortably watching Rainbow attempting to gain a new nickname in various ways, the worst of which being a severely misjudged sequence where she imitates her friends in order to make a different impression. It's not a bad idea, but in context it's little more than watching her embarrass herself further to what we know will be no gain. The end point is predictable, so watching Rainbow go to such lengths is unpleasant rather than entertaining. In addition, because the end point is so obvious, it's doubly grating that they didn't do anything else with it. A stronger internal conflict for Rainbow would have made for a more interesting episode, and even if it would have complicated the main themes, they probably still would have come clearer than they do after watching Rainbow Dash grow increasingly desperate.
That combination of uncomfortable scenes, wasted potential, and poor execution severely limit what could have been a fairly decent episode. "Newbie Dash" has the right ideas, and it's frequently watchable, but it could have been so much more, especially given just how significant the event at its core is. This is Rainbow Dash becoming a Wonderbolt! It should have been an episode which really shows off why the character is interesting in the first place. Instead, Rainbow's characterization seems to be moving backwards if anything, and all of the episode's most interesting ideas aren't fully fleshed out. I really do think that the episode was on the right track, and it's not terrible, but it's an even more heartbreaking disappointment than "No Second Prances" and a very bad omen for the season's direction.
And season 6 seemed so promising at first.