Unfortunately, delays are normal in game development. I've seen mention of a few high profile games in the last couple months having their releases pushed back, even if an exact date had been stated, rather than just a general time frame.
Most RPG fans value story and gameplay above graphics (except action RPGs, which lack substance and need to make up for it with cosmetics). While magazines and some websites may score lower for 'last year' quality graphics, I don't see that as being Larian's biggest potential problem.
The difference between this year's graphics and last year are not really that great any more, especially given the prevalence and expected longevity of the XBox and its graphics limits.
Many story based RPGs do just fine without multi-player to keep them alive. If some form of multi-player gets added to D2:ED it would be a minor enhancement IMNSHO, nice to play around with a bit, but I don't know anyone that could match my schedule consistently enough to finish a 50 hour game.
I think modding tools would be better at keeping the game alive than multi-player.
If graphics are a primary feature for you, then by all means buy newer games with more eye candy.
Thieves use many excuses to justify not paying for things, almost all of which are completely bogus. What any person with any integrity does when they don't think a game is worth the current price is to wait for a sale or a budget re-release a year or two later.
I don't think Larian is/was unaware of any of the problems a delay could cause. The release date is up to the publisher, which has been officially announced as during the holidays (and unofficially listed a couple places as January 5th).
