I suggest leave when they play.
Yeah it's really annoying when you think of how many great band could have played in their spot, but throwing and booing isn't gonna work either.
Just ignore them. It's way more irritating for a band to play in front of nobody and get no reaction/attention then face a hostile crowd. A hostile crowd could motivate ''bullet'' to win them over. There are enough other options and places to go when these faggots play.
I have to say some change isn't bad. The choice to book Machine Head, Fear Factory, Ministry etc. was very good. But they earned their place.
To book some other bands than the typical Wacken bands is not bad, but ''bfmv'' is way out of line. We go to Wacken to escape those shitty festivals, and now this?
Some bands that never played or haven't played for years -(I know some of them played Wacken before, but I visit since 2003 and they havent played since)- and some that are different from the traditional Wacken bands, but would fit way better:
Judas Priest, Type O Negative, Danzig, Down, Black Label Society, Superjoint Ritual, Outburst, Eldritch, Seven Witches, Dream Theater, Dark Tranquility, Vanden Plas, Oceans Of Sadness, Scar Symmetry, Life Of Agony, Lamb Of God, Pro-Pain, Naildown, Ted Nugent, Pro Pain, Perzonal War, Devin Townsend, Raven, Angelwitch, Exodus, Agent Steel, Corrosion Of Conformity, Talisman, Chincilla, Armored Saint, Iron Savior, Steel Prophet, Soul Doctor, W.a.s.p., U.f.o., Lost Horizon, Detonation, Suicidal Tendencies, Winterlong, Strapping Young Lad, Tankard, Monolith Deathcult, Riot, Deadhead...