Well this will just make it harder as you will still do the same but also try to keep your guys in cover.
Enemies don't trigger on their turn if you're in cover through, even if in vision arc. They only do if "flanked", therefore not in cover, therefore they shoot your butt.
I didn't listen to video, only watch it. Did they say this?
If this is true, people will abuse that even more as it will let you get closer to them than ever and kill them on your turn.
So.. the way it was intended. This is what we call overwatch trap, welcome to xcom.
And they still do skittle about if none of your soldiers is blatantly out of cover.
And yes, if you are in cover (at least from enemy approach side) you will not get discovered if n their vision range. You can't leave your spot though or get discovered. because movement in that range (even between covers) is a giveaway.
Xcom 1 didn't have this. They spotted you from far away, you could not place your guys all super close and then trigger them. Now you will place everyone within one move distance, trigger them with one then use others to move next to them and blow their heads off with critical hits. At least in Xcom 1 you have to maneuver enemy AI so your other guy from out of sight going around to flank can get close enough so next turn he can move next to enemy to blow up their faces.
The concealmeant break is SUPPOSED to be a gimme. If you use the gimme to get one of your squad members fatally injured, you're using it poorly. The "fix" they came up with is surgical and pretty smart, since it disincentivizes that trick except in very weird scenarios (max armor heavies, maybe, using smoke + defense protocol from drone, etc), while not affecting the way most people play.
People who think putting a guy out of cover to intentionally trigger that behavior is a good idea haven't really understood how the new concealment system works, I think.