I'm old enough to be completely with Teague on this. Episode One of any show is the sales pitch to the audience for the rest of it, and needs to be built accordingly.
As with any sales pitch, it needs to grab my attention, then deliver the whole pitch before it loses my attention. That pitch needs to amount to "stick with us, it'll be worth it."
I'm not remotely interested in listening to any show warming up or finding its voice over the course of some indeterminate number of episodes; life's too frigging short, and the writers and producers should have done that already before throwing the monkeys in front of the cameras.
Several of the shows mentioned above have the advantage of having been left on the air long enough to find a voice that we can now talk about, but that's with hindsight. Plenty of other shows remain uninvolving, and I don't think it's my job to pay out a load of attention rope to a show just in case it finally grabs hold of it.
Now, this doesn't always work out: FlashForward's pilot had a bunch of momentum, and then stalled for most of the rest of the season before blowing up the gear box in a panic at the end; Heroes had a stonking beginning, and only really turned to mush in season three.
I've repeatedly heard the claim that it can take a show three seasons to get really good, and the 'evidence' for this is Star Trek: the Next Generation, which does, indeed, have a truly horrible pilot. (So horrible, that my girlfriend and I literally gave up on it partway through, and didn't see the rest of it until years later, after catching a few season three episodes re-engaged us with the show.) However, I think this claim is as spurious as the claim that it takes Microsoft three goes to make any product good (based on Windows 3.0 being the first non-terrible version).
ST:TNG might have convinced Rick Berman that he deserved three seasons of our attention to get his acts together with DS9 and Voyager and Enterprise, all of which underwent significant changes during their respective seasons three, but that was just a cheap excuse for not being ready at the start, and he was less able to get away with each time as we had more alternatives to just sticking with it.
If you're producing a new show, you need to grab my attention and win it with Episode One, don't just expect that I'll donate literally days of my life to you on the off-chance that you might get your act together once you've learned how to write what you want to say.
