Well ME2 already comes with a character creation function for those who can't/dont want to import a ME1 save, does it not? I don't see it being much of a hindrance. It'd be nice of them to include that "Story So Far" video as an extra for those that've never played the first one, but it's by no means a vital inclusion.
The problem is that over a hundred decisions carry over to ME2, and if you don't have an ME1 save then those decisions are all made for you: Wrex is dead, the Rachni Queen is dead, and so on. Most importantly, it was strongly hinted in ME2 that the decision to save the Rachni Queen would be helpful in ME3, but if PS3 owners don't even have that option, there's less incentive for Bioware to make a big deal out of that in ME3, which is disappointing.
They could include an extensive list of all decisions from ME1 when you're making a new character in ME2, but how many people will want to start a new game by selecting over a hundred options about which they have no understanding of the context? Without doing the Noveria mission, how can you have any understanding of which decision about the Rachni Queen "feels" right for your Shepard?
I'm glad that PS3 owners will finally be able to play this game, everyone should have the opportunity to play it. But it sucks that they're not going to get the full experience from it, and I do worry how this might impact ME3's story.