Maybe the downfall of Star Trek really is all Rick Berman’s fault after all.I say that because to start his post-Trek career, the other half of that joined species known as Bermaga has created what is arguably the best of the new network alien-invasion series.I say that as someone who expected to despise Brannon Braga’s “Threshold.”However, after watching all three of the new network aliens-among-us shows, “Threshold” stands out: It’s only one that’s really captured my attention.Comparing and contrasting “Threshold” on CBS against its competition–ABC’s “Invasion” and NBC’s “Surface”–is made easier because all three rivals start out remarkably the same.It’s almost as if all three started out being written by the same guy.Not only do they all revolve around the coming of otherworldly creatures, …