Ronan was defeated by a demigod who had an Infinity Stone. The dance-off was merely a distraction.
Thanos - and this is just the wildest of speculation - will be defeated by six heroes each wielding an Infinity Stone.
Soul Stone - Adam Warlock Time Stone - Strange Reality Stone - Nebula Power Stone - Captain Marvel Space Stone - Thor Mind Stone - Hulk
Vision will likely be destroyed when Thanos takes the Mind Stone. Star-Lord cannot wield the Power Stone like he did at the end of GotG because Ego died and he has therefore lost his ...godhood. The Soul Stone is presently unaccounted for but a current theory says that Heimdall has it and that's how he's able to see everyone.
I really hope the DCEU will succeed. Sure, they have better characters than Marvel, and those characters, when treated right with the right actor, can make a great movie (wonder woman.)
But too many times already, in just 4 movies, they have rushed things. We should have got stand alone movies for Batman and Wonder Woman before BVS. They are rushing to play catchup with Marvel, but they are 5 years and 15 movies behind. With rushing comes bad story telling.
Now all the most important characters are being thrown together in Justice League, 4 movies in. 4 movies in which only 3 League members have been explained, 1 of which is "dead." Now before JL, only 2 have had stand alone movies. Before the first Averages, 5 movies had come out, introducing 4 avengers, all of whom received stand alone movies before being thrown together.
DC needs to stop rushing, and plan for the long haul. And their writers and directors will probably stop quitting if they get more organized.