The delayed crumbling of the Espheni tower after one hit by the Volm weapon was very nice, even if the victory over the Espheni was predictable. Similarly, the Volm turning out to be not quite the saviors they seemed was thoroughly predictable, though the father and son Volm interaction was a nice touch. And the survival of Anne and Lexi was thoroughly predictable - I didn't think they were dead in the first place (they looked like they were in some sort of suspended animation) - as was Lexi's advanced powers.
But - the nature of Lexi's powers was a great last touch. I had thought she had some kind of Espheni or bad-alien DNA - the source being Tom (which he received when on the alien ship, was my first hypothesis) and then Lourdes (who had taken care of Anne during her pregnancy, and could have easily introduced some alien DNA).
Those hypotheses are still possible, but what now appears not be the case is that the DNA was from the Espheni or their bad allies. Because in a great ending scene, Lexi - now six years old (she achieved this age in just two months) - not only draws out the worms from Lourdes' eyes, and takes them in her hands and turns them to dust.
Not only is this an impressive power, but it calls into question - again - just what Lexi is? She's obviously part alien, but what kind of alien? Possibly the DNA is indeed Espheni or similarly-hostile alien, and Lexi is using her powers for good, because after all she is at least half human. That would be a nice, logical explanation. But I'm thinking there's more here, and for that reason - in addition to enjoying how the series pivots so well, yet maintains its identity - I'm much looking forward to season 4.
And see also Falling Skies Returns ... Falling Skies 2.6: Ben's Motives ... Falling Skies Second Season Finale
And see also Falling Skies 1.1-2 ... Falling Skies 1.3 meets Puppet Masters ... Falling Skies 1.4: Drizzle ... Falling Skies 1.5: Ben ... Falling Skies 1.6: Fifth Column ... Falling Skies 1.7: The Fate of Traitors ... Falling Skies 1.8: Weaver's Story ... Falling Skies Concludes First Season