Oh the irony - a song from the Watchmen soundtrack no less! 😀
I don't think BvS was ever "surefire", other than it'd make tons of money. It was never going to actually be critically good. Because Zack Snyder is about as divisive as a director you could get that isn't called Michael Bay. (he also directed Watchmen, hence the irony!)
I'm the first to admit, I'm not a DC fan. I'm a Marvel girl through and through. Sure, the MCU has had its issues, and some near miss flops. I had issues with Age of Ultron, Ant-Man and Iron Man 2. I'll never admit that everything they put out is perfect and without flaw (except Thor, it's a masterpiece of modern cinema), but as soon as DC announced it was fast-tracking its DCEU, I knew they were making a mistake. They wanted to emulate Marvel's success by taking its two key players, each successful with their own movie franchises and bring them together on the big screen, and they wanted to do it fast, with very little planning and execution, unlike Marvel who spent years building up their key players.
I'm not one of these Marvel fans who pass judgement on movies I've never seen. I liked Nolan's Batman trilogy. I liked the original Christoper Reeve Superman (still seeing it today makes me feel like that amazed kid seeing a man fly through the air for the first time). But to be honest, it's never interested me seeing Batman and Superman duke it out. Because one's a human with loads of money and gadgets and one's an immortal alien with superhuman strength and powers. And I really disliked Man of Steel. I don't think it was a good film.
Saying all this, DC has done two things absolutely spot on and much better than Marvel. Firstly, they announced Wonder Woman headlining her own movie, when Marvel has been putting off a female-led movie with Black Widow and late in the game with Captain Marvel. I hope it's not too little, too late in that regard. They should have just given Scarlett Johansson a BW movie, instead of claiming the fans would never want it. I know plenty of fans who would. In addition I'm super excited for Suicide Squad, because it looks like a risk. The sort of risk that Marvel Studios (and their owners Disney) would never take. If the DCEU is willing to take risks on their material, they will bounce back from any negativity surrounding the critical panning of BvS.