Sentinels, in theory, are agents that specialize in holding space for long periods of time, mostly defensively. Sage can wall off areas of the map and deny the enemy space with slows. Cypher and Killjoy have traps and intelligence gathering systems. They're textbook Sentinels. They have primarily defensive util. This concept is why Viper can be considered a semi-Sentinel, like she is in pro play: her fuel system and mollies allows her to defensively control space throughout the map for extended periods of time.

But just slapping traps/defensive util on an agent and calling it a day will get super boring pretty fast. There's only so many variation of traps you can do. And eventually, putting too many trap agents in the game can make the game kind of unfun and slow in the long run. Because of this, the Sentinel role is constantly a threat for long-term game health, and Riot must be careful whenever they add a new Sentinel, while experimenting with other ways of holding space defensively.

Riot tried something different with Chamber, by making him a more active Sentinel that relies on superior weaponry and elusiveness to hold space. He essentially holds space by being an absolute menace to enemy players, with the help of a trap. It pisses me off when people call Chamber a duelist, when he's not. Duelists excel at TAKING space. Chamber is terrible at taking space, but he used to be damn good at holding it. But they took it too far, and Chamber ended up an overpowered monstrosity that had to be gutted. We'll see if they ever consider changing him in the future, because buffing him could be volatile.

TLDR; There's only so many kinds of traps and defensive utility you can add to the game without just making it redundant and slowing the game down overall. How do you guys think Riot will try and tackle the new Sentinel that will be with us in a couple months?