Well, I liked it at least.
Some may call it slow, but I don't see the pace as really being any different from the first four seasons. They all started fairly slowly, with the tension not really ramping up until episode 8-9 or so. The show is great at set-up. I think the different feel this season is that it's trying to deal with more stories, while the others have generally had one main arc. That's not necessarily a negative in my book.
I'm still interested to see where Lumen goes as a character, and Julia Stiles has been impressing me more than I expected. Like others, I hope it goes somewhere unpredictable though. Just once I'd like the season's "special guest star" to live through the end...
I hope some of the other plots pick up, like Quinn looking into the ghost of Kyle Butler, and Deb learning more about Dexter (I imagine these will be intertwined in the end, and Deb has other priorities right now). I'm liking the supporting characters like the nanny and the officer Deb is working with, even if their story hasn't grabbed me yet.
As for Batista/LaGuerta...sigh. The writers still just don't seem to know what to do with them, but insist on giving them their own plots. If nothing else, while Angel's jealousy and bull-headedness may be annoying, at least it's consistent with his character from right back to season 1. He's always been overly passionate and thinks with his heart rather than his brain. And LaGuerta's always been stubbornly independent - her not communicating enough, even with her husband, doesn't feel out of character.
I have no idea who Peter Weller is, but that accent he used drove me nuts. I agree in hoping he tones it down a bit...