I need to watch the last several episodes again and sort of analyze Flack's behavior.
I could be wrong, but it seems to me that the friendship between Danny and Flack is more in fandom than it is canon. Danny seems to be closer to Hawkes than Flack, especially now. In season 1 we heard them planning to shoot hoops on Saturday and we've seen them work a few cases together but not as many as Danny and Hawkes have worked, and lately there hasn't been much in the way of any friendship dynamic between them that I have noticed.
In Raising Shane we saw that even though Flack works with Mac's team, the Captain is his boss and his first loyalty is to him. Whether we like the Captain or not (and I didn't) we see that he is in fact Flack's boss, not Mac. There's been discussion about how Flack lives in both worlds, and he does, but he's a cop first.
I think the cops who are talking about Flack, bad-mouthing him for handing over the memo book are small-minded at best. I mean, come on, do you *want* a bad cop out there making it harder for the honest ones? Get serious. They'll get over it, I think. It might be tough for Don right now but he did do the right thing and everyone will see that in time. It would be interesting if we saw a follow-up to this issue at some point.
It does seem like Flack is an under-used character. Hopefully they will do a good back-story episode about him at some point. Like they did with Brass on the Vegas show. I'd like to think that since they know what a great actor Eddie is that they are working on something that can really let us see his talents. They've done that with Carmine, several times. His work in Raising Shane was stellar. Of course having an actor like Edward Furlong to play against didn't hurt. That guy is awesome. Maybe they will wrap up the Danny-Lindsay thing first. I'm trying not to speculate about that, but rather just wait and see what happens. I seem to be one of the few people who can actually relate to Lindsay.
Anyway, I was supposed to be talking about Flack. I can't believe that with all the potential stories they've set up, that they won't give us a great Flack story at some point. There are many, many possibilties.