What is the problem with changing discs exactly? It takes like 30seconds. In fact MGS4 where a huge deal was made of how it would need too many discs on the 360 I would argue would have benefitted from multiple discs rather than being on one disc and needed to install chapters. A process which takes much longer than changing a disc.
Would I have liked to have paid an extra $200odd so that LO came on one disc instead of 4? Not a chance in hell. When blu ray is cheap enough to be included reasonably then fine whatever but it definetly isn't something I would pay a premium for.