Just a suggestion, but I think the remaining corpses of the dragons isn't helping the lag issue cause. Personally, I could care less if dragon corpses remain. Equally, they are annoyingly in my way in certain places (a dead dragon right in front of the gates of Riften). Get rid of these persisting corpses, Bethesda. They don't need to be there and I now avoid dragons so as not to accumulate more lag/random bodies. They should be a joy to kill, not a persisting, blocking annoyance that induces lag.
Overall, great work! Just want you to know that.
Stats:
PS3 Slim (1 year old)
73 hours played
Level 46
Dragons killed: 27
Quest Completed 104
Lag persistent and noticeable after roughly 3 hours or so from a "fresh" start of 12 hours of downtime or more.