Majoru, you could sit at my games any time -- my players rarely let me go on with a description for more than a few sentences ("Now wait a minute... I want to roll initiative before the orc cuts down that peasant! Yeah, I know, it's supposed to be a boxed text and all, but no way am I going to let that beast get away with it!").

So, you could say my players are very "proactive" (if that's even a proper English word?), and I'm completely fine with it; if a player disrupts my monologue, it means that he's doing something instead of passively listening. Although I only very rarely go on a "rambling" mode -- my own style is actually a mix of description and "prompting", i.e. I always pause after a few sentences to see if the players intend to do something (although they rarely wait for that long) and if not, I'll ask them if they want to do something. And if a player interrupts my description with an action, I roll with it.
What I thought was the weirdest thing was that the whole slaver encounter was screaming (at least to me) "
Skill Challenge time!". And even if had come to blows, who cares about tracking them? Another Skill Challenge (Intimidating a survivor, using Nature to estimate their course, and so on) would have solved the issue. This sort of thing is where 4E shines, so why didn't the DM say 'yes'? The only explanation that comes to mind (also based on their expressed views) is that they regard 4E as an "inferior" system, and even the DM hasn't bothered to read the rules (I wouldn't be surprised if he doesn't even know what a Skill Challenge is).
I've played (and still occasionally play) under such a DM; he likes descriptions, complex plots with subtle clues (most of which goes on in the background and in his head; we rarely discover those clues, and even less about the metaplot), "punishing" active players who think outside the box (i.e. try to find ways that bypass his plotted course). Most adventures are solved by "triggering" NPCs and events in a rail-roaded, prewritten script (just as in computer games) -- and, like I said, usually the subtle hints are, well, so subtle that even attentive players easily miss them (and there's no "prodding" from the DM, ever). What a joy to spend three sessions in a row getting constantly hit with random encounters because we're going on wrong tangents and following "wrong" clues or trying "unscripted" stuff (the worst sessions are the ones in which we desperately try to avoid needless combat by "staying put", and wrack our brains to come up with the correct "solution"... it's just some role-playing and throwing ideas OOC with minimal DM interaction, and nothing, absolutely NOTHING happens). Well, maybe the DM you described isn't as bad as this, but I wouldn't still enjoy playing under him.