Nothing at all is sacred in Hollywood but sometimes that isn't the end of the world at all. Star Trek was successfully rebooted in 2009 with JJ Abrams' films, and though Leonard Nimoy, William Shatner, and Deforest Kelly all seemed irreplaceable, the cast in those films was actually spot on. So much so in fact that with the sad passing of Anton Yelchin, there have been many calls to retire the character of Chekov altogether.
While there are many (including this writer) who would take the news of a reboot of Deep Space Nine with... hesitation... that doesn't mean it isn't fun speculating about who could step into those roles if the situation arose!
Now this entire post is entirely a bit of fun speculation - budgeting for these players plays no part in this dream!
For the past several years, television has been enjoying a golden age of high production values and output. Star Trek: Discovery and Star Trek: Picard both look superb, and the animation on Star Trek: Lower Decks is glorious. What is certain is that, if Deep Space Nine were to be rebooted, there would be stunning new depictions of the station, of Bajor, and even the Wormhole itself.
So, take a leap of faith, and let's see who could be manning that lonely station on the edge of the final frontier.