By spoilered do you mean they've artfully crafted a trailer that doesn't ruin any surprise, or do you mean they spoil everything?
I think spoiler is a pretty commonly defined and understood term so I will politely simply answer that it is the latter, in the case of BvS. The former pertains more to something like Doctor Strange.
Doctor Strange didn't show its entire hand before the movie even premiered (yet, there might be some of that in a third trailer between now and November), unlike BvS. Thanks to the volume of information spewed forth by BvS' abundant trailers and other promotional material, we knew Lex was responsible for (and that there would be) Doomsday and that it would bring the heroes together even after having been fighting each other thus neatly resolving the conflict between them and fulfilling the 'Dawn of Justice' subtitle; Wonder Woman was unable to remain a pleasant surprise; that they were hinting at a conflict with Apokolips/Darkseid (instead of doing something like the Avengers where Thanos was relegated to a post-credits scene only); that Kryptonite was going to be the means by which Batman was going to tangle with Superman on an even footing; that Batman was now an unfeeling murderer (not so much a spoiler as a sign of something very, very wrong with many people's favorite character); and hinting that Lex knew everyone's secret identities from the very beginning (though HOW he figured all that out never actually got explained, so it was even worse seeing it in the actual movie.) The movie blew its entire wad far in advance and the end product didn't even seem to tie it all together in a pleasant, enjoyable way. Who knows, maybe if they'd at least left a little bit of it up to people's imaginations, their expectations might have been different and would have led them to be a little less critical about it. But I doubt it, if only in this particular case.
Doctor Strange, at the very least, has some mystery to it even after two trailers have dropped. Baron Mordo is way, WAY different than in the comics, which is a huge twist that renders his role highly unpredictable (although he does seem to be on Strange's side, more like a friend than even a rival at this point; the possibility for them never becoming enemies is not even out of the question). The villain is (at least to me) an unknown, nor can I predict which of the many malevolent otherworldly entities which he might serve or what their particular intention is. The full extent of Strange's powers is still unknown, as are those of his allies (and enemies), and how any or all of the shown relations will change in the end. Also now that Marvel is basically opening the floodgates to their supernatural realms, the ramifications this will have for the rest of the universe, both the ABC networks shows, the Netflix shows, and other films, is subject to big (but still somewhat unpredictable) change.
Almost none of that is left to the imagination in BvS, just by comparison. So I would say that the approach they took with the trailers for that, at least, was a pretty poor idea. As long as the trailers aren't entirely misleading, it's fine, and expected, to leave some things to speculate about. Telling us the story in its entirety in the span of a two-minute trailer, on the other hand, is a total shit idea and any movie would do well to avoid that even if the story is basically an archetypal formula. As long as important specifics are avoided, it can still feel fresh and intriguing. Much as I hate to admit it, even Fant4stic didn't make those mistakes in their trailers.