Film Review- Dark Shadows

Hey guys, 
Recently I just watched 'Dark Shadows' featuring Jonny Deep and a star studded cast. My reaction couldn't be more disappointing. At a 12a I believed that it would be a funny, casual movie to watch with my younger sister. And I wish I'd read the reviews, I heard the 's' word more than once and the references to suicide, drugs and laden with innuendos I was shocked, let's not forget the violence. Another thing I should have checked was the director; Tim Burton. In no way is this film to blame completely down to him but rating this at a 12a is by no means an ideal certificate for this film. The trailer really deceives me; thinking it would be something within the context of "Hot Tub Time Machine" in that retrospective. I thought it would be humourers it being set in 1975. This is another thing that baffles me; if this is a film targeted at kids; which suggests the loose 12a rating; why the hell set it in 1975?! Surely kids are more likely easily able to relate to things within their range of being born. I was born 1994, my sister 1999, so why not set it in the early 200's. Surely a lot of jokes could be made? This is just a mere suggestion; my sister failed to understand what half the jokes were and the first crude reference to being stoned left her baffled to what being stoned was. In no way is she naive; in this day and age I fail to understand naivety. Even within my family, being well raised  and reared naivety is still a precious thing. However; this is a film I would have the parent advisory sticker on; they don't even have that any more I don't think. BUT PLEASE ENTER WITH CAUTION ON THIS FILM. I wouldn't have watched it had I known the crudeness of this film. 
Secondly, this is my own personal opinion; the casting and basic plot line was intriguing and catching. It's just the other elements that make it hard to watch! 
Kind regards,
TSITR