There's tons of plot, there's just no coherent connection to them all so it seems like a jumbled mess with no plot.

That's because the Marvel Cinematics has mutliple entries to give adequate screen time for most of what's going on in it's universe.

However, What people are saying is that BVS felt like they smashed together what could have been 3 different movies just so they can establish the DC Universe as fast as humanly possible and play catch up with Marvel.

You can't succeed in using 2 Movies to tell the same level of complex plots as what took Marvel 5 Movies preceding The Avengers.