So you'd rather be told your never getting Dawnguard then "were still working on it" which has been said every few days either through twitter or say in the Hearthfire articles where they assure players the team working on hearthfire was independent of the one working on Dawnguard. I'm sorry "still working on it" isn't a good enough answer for you. But thats the only answer YOU are anyone is going get until the problems are solved.
I once spent hours trying to figure out why a laptop couldn't connect to the wireless network and every five minutes someone was whining how much longer. What they could never grasp was if I knew how long it take then I'd know what cause of the problem was and I'd be finished. Dawnguard is little different then that. If Bethesda knew how long it take them to finish they'd be just about done.
If the "We're still working on it" is just to keep people from boycotting Dishonored, and once that game drops they'll come out and say "We can't figure it out, so you're not getting it," then yes. I'd rather they just admit that we aren't getting it and be done with it. To be fair, if that is the case, I'd be doing the exact same thing they are now. I wouldn't admit it until I could ensure that the sales of another game at launch will be affected by this as little as possible.
Also, the whole thing about Dawnguard on the PS3 not being delayed because Hearthfire was developed by someone else isn't exactly true. They're different teams, but that's still splitting resources, having people code new content when they could be working on figuring out what's wrong with Dawnguard. Unless Hearthfire has no debugging team (which again, wouldn't surprise me if that was discovered to be the case) and those who would be debugging it are working on Dawnguard instead.
All in all, given their past behavior, the idea that Dawnguard has been delayed due to quality concerns on the PS3 seems a little disingenuous. Don't get me wrong, if they actually are working on making sure the game isn't unplayable when its released, good for them. I expect that in products I buy, but given their track record, it's hard for me to buy in to the idea that we're going to get a properly debugged game.
I'd rather know exactly how big the team working on Dawnguard on the PS3 is at this point. I don't suppose it's very big.