All fair points.
I think I'm worried about them going Lost on us. The more convoluted the mythology gets, the harder it is to weave it all back together into a coherent narrative.
If Agent Howard was a cop (or some such authority) from their world/dimension/whatever, then why was he Jennifer's adoption agent? And then now they just casually throw in the fact that Dave was adopted too? Hmm...
I do like how creepy and evil Sheriff Carter is. Excellent considering how effortlessly good he was in Eureka. But I think it's going on too long. JMHO.
Hopefully we'll get a solid finale before the long wait until next season.