Sometimes, we as a people focus at just the big things and overlook the little. The bigger, more boisterous details we see in the show are the most upfront, but objectively good episodes like this, Slice of Life, Amending Fences, The Mane Attraction, and The Cutie Map are beyond the grand. Little pieces of detail are often overlooked. More often than not, they're the glue that holds the pieces together.

1. Would the moral for Slice of Life make any sense if the animation and position of all the characters were inconsistent?
2. Would The Cutie Map's setting feel creepy if the dull colors, equal sign layout of the town, lack of town name, and the nervousness of the mares during "Our Town" were completely opposite?
3. Would Moondancer's resemblance of Twilight make sense if she looked like somebody else?
4. Would The Magic Inside be as powerful and emotional if Ingram sterilized her voice?
   

The one answer for all four is no. Each of the details have poignant purposes. Change 'em in any way, and you damage the credibility of the story.

Crusaders of the Lost Mark is no exception. There are very obvious moments that helped shape the story. But two littler moments really gave the episode shape.

1. Princess Celestia assigned the Mane Six into removing the hibernating dragon. Why is this a problem? It makes Celestia look inept as a leader. If she didn't know about the dragon at any point, then perhaps the journey to remove him would have some weight. Instead, "Please move the dragon for me; I'll sit idly by and have some tea." Why do you have to make Twilight and her friends do the job for you? If the Mane Six knew about it from the start and decided to try to move him on their own, then I'd buy the story much better.
    
   This ain't the case for Crusaders of the Lost Mark. So many bronies' favorite moment of season five is the CMCs receiving their Marks. And who can blame them? It's a fantastic moment that capped off a truly remarkable journey to earn 'em. But my favorite of this season is them following Diamond Tiara to see if she was okay.
    
   
   Think about this. Throughout the show, Diamond Tiara and Silver Spoon bullied the CMCs. Mocked them for their lack of mark. Bribed and manipulated them into releasing mean gossip. Coerced Babs Seed to turn on Apple Bloom and physically abuse them. Mock Apple Bloom for not wanting to participate in Family Appreciation Day. Bashed Scootaloo in ableist language. Will you blame them if they saw Diamond Tiara lose her friendship with Silver Spoon and chuck any goodwill at her away? No!
    
   Instead, they felt worried and followed her to see if she doesn't do anything reckless. With that moment, the Cutie Mark Crusaders show to us as viewers how much they have grown. If this happened in, for example, season two or mid-season three, then it'd be out of place and (dare I say) out of character of them. However, over the years, they developed into fantastic, well-rounded, mature characters. They're still child characters, but they grew as much as anyone in the main cast, if not more so. They didn't sweep any of her evil under the rug; they followed her and were worried for her wellbeing while acknowledging the gravity of her terrible deeds.
    
   If Cheerilee asked the begrudging trio to follow her and see if she doesn't do anything reckless, how much would you buy the story's credibility? Not much. The musical and overall plot would carry little weight, because it comes across as a homework assignment thrust upon them rather than a choice to help her. By deciding to help her, the journey to Diamond Tiara's redemption and the CMCs earning their cutie marks makes so much sense.
2. What do Keep Calm and Magical Mystery Cure have in common? They each try to come up with very significant outcomes that break the status quo. But their inferior pacing damages the story's credibility. Besides being self-contained, observe how long it takes from the beginning of the episode to the end. Discord's redemption and Twilight's ascension took place in at most twenty-four hours, if not shorter. Discord is a god who shoved chaos at everyone's expense, and he became reform before sundown. In the morning, Twilight was a unicorn having a typical morning; that night, she became an alicorn princess. These are two significant moments canonically, but them being crammed in a twenty-four-hour window is incredibly implausible.
    
   In Crusaders, that problem was settled during Act 2. After seeing Diamond Tiara's mom psychologically abuse her, and Diamond Tiara hit rock bottom with no clue to figure out how to change, the Crusaders elected to come up with a plan to help redeem her. By having the time skip, the audience is told that they didn't rush their plan. Instead, they thought about how to help her change.
    
   This is why the criticisms of Tiara's rushed redemption is misguided. If the Crusaders decided to immediately ask her to come to the clubhouse, and the Crusaders earned their mark that evening, then I can understand. But the time skip shows the Crusaders' ability to pace their plan AND forces DT to think about what happened yesterday. The script didn't make her forget about her falling out with Silver Spoon or Spoiled's abuse. She constantly reminds herself, and we're reminded back. It drove the point very subtly and was focal into Tiara's envy inside the clubhouse, the chase sequence, and Tiara finally standing up to Spoiled.
   

The time skip makes the sequence from the CMCs plastering more paper on the wall to their reward at least a two-day conflict. By making the conflict last two days, four major plotlines paced through spectacularly, and you don't have to worry about it feeling rushed. More importantly, as a result of the Crusaders willfully helping their enemy change her ways, making her a good friend, and Tiara realizing her capability of using her talents for good on her own, Tiara's redemption feels incredibly real, and the payoff at the end is so satisfying to watch multiple times over.

There are so many reasons why CotLM is the best episode of season five and the second-best overall. These are two. Small quantitatively, yet so important to the story's quality.