I'll wait here untill our site's expert comes to this thread... yes I'm talking about MikeB..
OK... My take.
Let's imagine the PS2 had a Blu-Ray drive, would that result into better graphics on the PS2? Well IMO, in general not really that much as DVD was a good fit for its SDTV targeted content. Only later PS2 games were using up full discs, probably some multi-disc exclusives would have seen fewer sacrifices to keep the game on as few as possible discs.
It would still have been beneficial though, for multi-disc games, being far more scratch resistant than DVD is also a definite pro and potentially there would have been far more capacity for including support for more languages, bonus content like 'making of' videos or games compilations.
With the HDTV era of console gaming, demands for more storage has gone up considerably. Before the XBox 360 launched it was reported from a developers event nearly all the XBox 360 developers there told a reporter they had issues fitting their games on 360 discs. There is a demand for more storage than DVD can provide regarding delivering higher quality textures and higher quality audio.
Unlike what some believe, the exclusive PS3 developers still make heavy use of compression as the Cell is able to decompress data faster than the Blu-Ray drive could read the larger data sets from disc.
The main benefits for the PS3 and I'll use Uncharted 2 in examples:
- More storage (allowing for higher quality assets/content including textures and audio and/or more varierty of this content, like in Uncharted 2 there are many very different yet very high quality environments and the game supports many different languages on a single disc as well).
- Scratch resistance
- Constant predictable streaming performance (this is how Uncharted 2 is able to work around memory limitations, streaming in more data when needed and is able to allow Uncharted 2 to stream data onto the harddrive to provide very seamless loading throughout the game without any needed game install, after initial bootup if you play this game you will not encounter much if any loading times while playing the game from start to finish in one go).