Varys died in the penultimate episode of Game of Thrones, which is easily one of the series' worst deaths. "The Bells" is certainly one of the most controversial Game of Thrones episodes ever, and it's not surprising that Daenerys' decision to torch King's Landing even after the city surrendered is the plot twist on everyone's minds. However, the episode began with another major loss, as the Master of Whisperers was slaughtered for betraying his queen.
Varys' death wasn't a huge shock - after all, Melisandre predicted it. However, after nearly eight seasons of being presented as one of the most cunning, capable men in the Seven Kingdoms, his death seemed to happen incredibly quickly. After a couple of conversations with Tyrion about Jon's claim to the throne, Tyrion told Daenerys Varys was betraying her. And so, Daenerys had him executed. Of course, Varys was certainly betraying the Queen, both with letters announcing Jon's bloodline and even potentially by trying to poison her. However, the issue with Varys' death isn't whether or not he deserved it, but that it's extraordinarily out of character for him to simply stick around and wait for dragonfire - and that, much like Littlefinger, Varys deserved a worthy death.
From Game of Thrones season 1, both Littlefinger and Varys were painted as two of the most intelligent and manipulative men in Westeros. Their differences lied in motivation; Varys always wanted what was best "for the realm," while Littlefinger wanted what was best for himself. They both rose to power from nothing and used that power to their advantages. But much like Varys, Littlefinger was killed shockingly easily. After seasons of intrigue, Arya killed Petyr Baelish. This came after Bran made it clear to Littlefinger that he was in trouble, and many fans thought that Littlefinger's decision to stay put was wildly unrealistic for him. Some even theorized that he faked his own death, a move that would have been much more in-keeping with his MO. But now that the final episode is nearly here, it looks like that isn't going to happen: Littlefinger is dead, and his death was definitely disappointing.
As disappointing as it was to see Littlefinger outfoxed by the Starks, his death was still a massive step up from poor Varys'. In many ways, Littlefinger's death still had all the great elements that Game of Thrones fans love: multiple factions attempting to manipulate each other, frighten each other, and generally out-do one another, culminating in a surprising death. The moment that Littlefinger realizes that he's the one on trial is stunning. He had a long and dramatic trial, after his machinations in Winterfell were built up over multiple episodes. Yes, he may have been too intelligent to be taken in, but he may also have become too comfortable, and underestimated the woman that Sansa has become. In addition, this death came at the end of an episode - and a season finale, at that. This made it one of the biggest moments of the episode, giving him his due as a major character.
Varys, on the other hand, had his betrayal built up incredibly quickly - he went from happily talking about Jon and Daenerys ruling together to trying to kill her within only a couple of episodes, and in few scenes in those episodes at that. He also doesn't get the trial and intrigue that Littlefinger did. Instead, it's simple: Tyrion tells Daenerys, Daenerys kills him. The closest he gets is a slightly sad speech before he's burnt alive - nothing compared to Littlefinger's much longer and more intense final moments. And of course, it's at the start of the episode, so that by the time King's Landing has been reduced to ashes, fans have almost forgotten that his death was even in "The Bells" at all.
Like many of the other issues plaguing Game of Thrones, the biggest issue with Varys' death seems to be time. Littlefinger's arc played out over a longer period of time. Meanwhile, Varys' death feels crammed into whatever few minutes the writers could carve out in the truncated season. He deserved to be a much bigger part of his final episode, to have an episode end with his death, or at least to allow him more of a final scene. A few sad words with Tyrion, and a complex character who is generally liked by fans is killed and then moved on from in a couple of moments. In some ways, Varys' death can be taken as foreshadowing, revealing Dany's mental state and willingness to kill with fire, but with a little more time, the entire scene could be made satisfying (if still sad). Varys' death should have been an episode centerpiece, but thanks to Game of Thrones rushing to the end, it's just a footnote.