So, limiting the discussion to dark matter and dark energy, which are still open to debate, it would be nice to have a score card of what is in and out.
WIMPs are out.
Mirror matter in and out, apparently.
String theory, in then out then in but not nearly as cool as it was the first time.
My theory is that fundamentally the big bang theory is mis-understood. The universe, as we know it, is currently under construction and subject to change. Not on human time scales, but if we wind back the clock and play it forward, the universe has been getting weirder. Look at the growth of the periodic table since the beginning of the Universe, the birth of protostars and galaxies, etc. I don't see why it isn't capable of continuing to increase in weirdness.
This begs the question of how is the Universe getting weirder. This is where the big bang theory draws dragons and warns of impending doom. I like to think of it as if two water droplets were coming together. One is red, one is blue. When they mix, they create a Purple center. Our Universe is the purple part. From inside the purple part, you can't see the red and blue Universes and it would appear, if you wound back the clock, as if the Purple Universe appeared out of nowhere and it would also appear as if the Purple Universe was not only growing, but the growth would be accelerating. This doesn't break the big bang theory and doesn't break any other known theories. It does remove the need to explain expansion and other observations.
Is that any stranger than mirror matter or string theory?