As long as it's not used for every foul/offside ect so it doesn't slow the game it's fine.
Should be like that every team has the possibility to demand a video review once or twice a match, not more. Not for every single scene. That 2nd English goal vs Germany at the 2010 WC is a classic scene for this.
On the CL: I think Barca will wipe Bayern off the field. I'm pretty confident, however, that Dortmund can do this. They met Real in the group stage and did quite well there (winning the game in Dortmund and draw in Madrid).