I'd like to think that whatever solution is being worked out by/with Sony, that eventually helps Bethesda get DLC up and working for the PS3 platform can't help but make the base game run better. The game being very complex, and quite large in content, it really requires a large team to attack and fix the problems, be they questline/content bugs or deeper seated game engine issues. One gets the feeling Bethesda has always allocated minimal resources to do the followup. It's like no one there wants to clean up the messes they've made rather they just throw some trivial new feature within a patch hoping no one will notice the smell didn't go away. Bethesda's leaders certainly aren't that worried about our displeasure regarding Skyrim' general problems, and the DLC as well, or they'd be talking to us. But they certainly are worried about whether or not they've lost a large source of their income in the future. Thats where the talk with Sony comes in....
Honestly, I do believe Bethesda has concerns that Sony might not certify future games from them if they don't get their act together with their current and forthcoming PS3 releases. I mean, why wold Sony support a company that is so inept at coding for the PS3 that some people are abandoning the PS3 and moving on to another platform once their threshold of frustration is breached?
That Sony didn't know of Skyrims defects to some extent, prior to release seems unlikely. But it's possible Bethesda played th, "yeah we know, we'll patch it later" excuse, which seems to be acceptable as an industry standard. I think Betheda has pushed that mentality envelope well past the bursting point with Skyrim. IMO the PS3 version was not a finished product, and should never had been released in the state it currently is. Bethesda's patches have essentially done nothing to strengthen the stability of the game on a permanent basis.