http://gaming.stackexchange.com/questions/34888/skyrim-ps3-vs-360-load-times
These average times have been posted repeatedly across the net by various sources, with a variance of a second or two here or there, but on most applications the game loads faster PS3. The only difference is the loading of a saved game, which comes off the HDD. That said, I know my load times are fairly quick compared to a stock PS3 since I upgraded my HDD a long time ago...but I don't take that into account because that's a personal experience, not the average clocked times and general consensus.
And where has this been proven? If you have a 12x BRD versus a 12x DVD drive, that bluray drive is going to blow the doors off that DVD drive. As I said before, the BRD for a PS3 is only a 2x which is comparable to the lower end speeds of a 12x DVD drive.
Now we could go into hypotheticals here with the ifs and buts were candy and nuts blah blah....but had the PS3 BRD been upgradable to even a 4x BRD, it's constant read speed would exceed the maximum a 12x DVD drive...remember, maximum. 12x DVD drives don't hit maximum all the time, not even half the time. Just saying, it just seems to me you know nothing about the difference between read speeds of DVD drive, the BRDrive, and how they function differently because a BRD has no min or max, it just is.
Sorry, you're claims are very broad and all-encompassing when you don't even seem to realize how fast a BRD can be.
And getting back on topic of Skyrim, Dawnguard, and the PS3, your claim that it is the Bluray's fault for the issues with the game is just absolutely ridonkulous. I mean, do you have any statistical data or anolysis that can prove this claim? It's just really farfetched and technically speaking doesn't make a lick of sense.