Boruto, as a Naruto sequel, has had a lot of ups and downs, although perhaps the biggest negative has been the impact it has had on the overall franchise. While fans of the original series can move away from the sequel if it's not of their liking, those who appreciate canon and worldbuilding can feel frustrated with some decisions, particularly with the power scaling creep and how characters like Madara Uchiha are impacted as a side effect.
It would be tempting for a lot of Naruto fans to say that Madara, widely regarded as the franchise's best villains (or at least one of the best), could solo the entire Boruto universe. However, considering the power creep that this sequel has had, a natural malice of the shonen genre, the reality is that the Uchiha ancestor wouldn't fare that well when compared to most of the series.
Disclaimer: This article contains spoilers for Naruto and Boruto series.
The impact of Boruto on Madara Uchiha's legacy as a powerhouse
It's interesting to look back on Madara's character at the end of the original Naruto series and see how the power creep in Boruto has tainted the villain's legacy. Granted, Madara himself could be a big example of power creep in the original manga but he had the imposing figure and legacy to back that up, which is why his status in the franchise now as a warrior is very sad to look at.
Whether it is the revived Madara who showed up in the Fourth Great Ninja War or the Juubi Madara who was killed by Black Zetsu, neither version would rank as one of the strongest in the sequel. This is a direct result of the aforementioned power creep and a general malice in shonen, where the latest villain has to be stronger than the ones who came before.
This is how the Boruto versions of Sasuke and Naruto could defeat him, how Baryon Mode Naruto is way stronger, and how several new characters such as Isshiki, Jigen, Shibai, and even Kawaki could be up there when compared to the Uchiha ancestor.
It can be a frustrating realization for fans of the original series who perhaps are not caught up in the sequel's manga, but is an embarrassing conclusion for such an iconic villain.
The overall legacy of Boruto as a franchise
The validity of Boruto as a sequel is discussed even to this very day because of the impact that it had on the original series and the characters a lot of fans grew to love. The Naruto manga didn't have the best of endings with the Kaguya twist and several writing decisions Masashi Kishimoto made, which is why a sequel right after the original story ended was perhaps something that hurt this project from the get-go.
However, there are some valid criticisms regarding the sequel, especially considering that the main appeal that it has is because of Naruto. Several beloved and important characters such as Shikamaru, Sakura, Kakashi, and a few more are sidelined heavily throughout the story, which makes sense in a way because this manga isn't about them. However, the trouble is that they are not removed in a way that feels logical or organic.
The aforementioned power creep is notorious, the worldbuilding was lacking in several instances, and while Blue Vortex has helped to right some wrongs in the series, a lot of people feel that it is too late for that. Boruto oftentimes feels like an afterthought in a lot of people's minds and has failed to grasp newcomers the way the original series. To top it off, the Madara situation simply doesn't help.
Final thoughts
Madara Uchiha is one of anime and manga's all-time greatest villains and his legacy is always going to be very significant to the Naruto franchise. However, the increasing power levels has made the character a lot weaker in the series' lore and that is something that a lot of fans have felt frustrated with, and rightfully so.