The fear of power creep has everything to do with trusting the players. There's this weird pervasive paranoia I keep seeing that any advantage the plyers find will be exploited with the express intent to ruin the game.
It isn't that players have "intent to ruin the game". The players get new shiny toys provided by WotC and want to use them, as expected, especially when they suddenly realize the new toy is just plain better
than their current toy.
So, again, in what way are you trusting them? To not use the new toy? Because if that is the case you might as well not include it if you don't want them to use it.
Trusting that they aren't out to ruin the game by exploiting the power creep toy? If you have players that you think have "intent to ruin the game" then my advice it kick them out the door...
If the players want to use the new toy it is because it is new
but often because it is better
in whatever manner (and perhaps in a way, more powerful?). Again, the DM either has to decide to: 1) allow it and deal with the new power the toy brings, 2) house-rule it so it isn't "better" but is still new, or 3) just ban it entirely.
If the new toy "breaks" the style of game you want to run as DM
through its intended use, you can't blame the players for using it if you allow it. I mean, are you really going to say, "Here, use this new power/feature/whatever which I recognize as too strong (or whatever), but don't use it so I have to adjust my style of game to compensate. I trust you to do that."???