I don't think there's anything wrong in making the Whitecloaks more of a threat. They can't switch villainous organizations nearly as often as the books can, so it's pretty clear the Whitecloaks will take over the role of a few other groups down the line.
What I'm not happy with is the execution of it all. There are in-book ways Valda could manage to kill sisters. Forkroot, or somehow getting them to a staffing. Heck, he could have a version of Mat's fox head ter'angreal.
We get none of that. I have a hard time taking the guy seriously after he dares Egwene to channel. He should have no clue what she's capable of, and risking everything believing she can barely channel makes no sense, withing the world of the show. He has no information for this at all.
In the end, it's things like that which bug me about the show. Not that they made changes, or even that they're big ones. The execution of those changes is annoyingly lacking, which is what bugs me.
You need to change the books to make it make sense for the screen? I'm on board. But then fucking make it work on the screen. If you take a big swing and miss, fine. But you keep doing that in multiple storylines, you lose my goodwill.
A good adaptation, more than being true to the source, should help you connect with it in new ways. Explore different facts of it, maybe.
The show so far has tried to do that, but in very amateur and hamhanded ways.