As of now, the MCU has put out two TV shows onto Disney's streaming platform Disney Plus, and they've both been incredibly successful. WandaVision had a totally different tone than anything else in the franchise, while still telling a relevant and classic story, and most people ate it up. The Falcon and the Winter Soldier had the pressure of continuing on the legacy of Captain America without Chris Evans, and also making something that tapped into very current cultural issues. Both of these series had an amount of pressure and risk with them, but probably not as much as the MCU's next series Loki.
The character of Loki was first introduced in Thor, of course as the titular character's brother. He's the God of Mischief, and while was at first a major MCU villain he's since become a bit of a grey area character and in some cases, an antihero. He's played by British actor Tom Hiddleston. Hiddleston was quite unknown at the time of his casting, but since has become a pretty big superstar because of this role. His fanbase, which is in turn also Loki's fanbase, is incredibly powerful. And that's kind of why the pressure is really on to deliver with this series.
Since Loki's introduction to the MCU, the power of his character has been felt. He instantly became a fan favorite, specifically with younger MCU fans who are very active on social media. This could have been because he's handsome. It could have been because he's a witty bad boy with a sympathetic backstory. It could also be because Tom Hiddleston himself is a very charming and handsome actor. Likely, it's a combination of all of these things. At the end of the day though, it doesn't really matter why fans latched onto him. It just matters that they did.
Though he has always been relevant, he's been a prominent character and a main villain, Loki has never been the star of the show. And in this series, his name is literally the title. It's called Loki. There's no doubting he will be the star of the show here. It's going to revolve around him, and it's also being rumored to have a huge effect on the future of the MCU. Undoubtedly, it'll hit big numbers. But if it's not a story liked by the fans, this could be catastrophic for the franchise.
As frivolous and pointless as it feels, social media and internet culture has a huge effect on the success of mainstream media. If something is torn apart online, this can be really hard to come back from. This is especially true when this works is something like Loki. With something Loki-centric being so anticipated, the pressure is on to deliver something awesome. Fans of the Loki character are also very, very active on social media and the internet. If they don't like it, everyone will hear about it, and that can have an impact bigger than one might expect.
Taking into account both what the average MCU fan wants to see, as well as something the average Loki fan will want to see, is also challenging. The two sides do overlap, but having a look into fan accounts online it's easy to see that there are some outliers. And these outliers can be very loud. It'll be important to produce something that can be middle ground and appeal to all, while also delivering on a technical level. This is a series that can't just be fine or good, it has to be great.
There is also an added pressure because the first two Disney Plus series performed very well. There was very high viewership, as well as very high reviews. If anything, their second series seemed to do even better than their first. That means there is a precedent set, and people are expecting something really good. The bar is getting higher and higher, when it was already high to begin with because of this being a show about Loki. That means Disney and the MCU have the opportunity to do something amazing here, and cement themselves even further as a massive media force. But they also have the opportunity to really fail.
If Loki is a failure, the MCU will of course still be very successful. There are many other projects to come, with many other opportunities to do great things. That doesn't mean this one is important. If it isn't as good as people are expecting it to be, fans will just be really disappointed. Undoubtedly, it'll still pull huge numbers. But there's more to being successful than that. The MCU has always made it clear that fans matter. Fan opinions and respect towards their fans, seem to matter to them. Some people will be so invested in Loki being amazing, that they will feel disrespected if it doesn't deliver. That is never good, and could be a stain on the franchise.
From what's seen of the series so far, it looks very true to character and very playful and different. That's a good sign, and fans are excited. However, with the series only just starting, it's unsure to know what public opinion will be when it ends. Surely, it's not lost on Disney and the MCU how important Loki is and they are likely feeling the pressure.