Re: SUPER UBER SPOILERMANIA: The Ending... What Does It Mean?
I think the answer to what really happened has to be more complicated than just "Loki faked his death, went to Asgard and overthrew Odin". For one, even in his weakened state I think it would still be pretty difficult to simply overpower Odin. Secondly, I kind of agree with the earlier poster who suggested that Odin knew he was talking to Loki when he was speaking with the guard about "'finding a body'. I am intrigued by the idea that Loki actually died and made some sort of deal to return.
Lastly, are Loki's illusions corporeal? In Thor they weren't (at least in the battle with the Frost Giants). It would have to be a pretty advanced illusion for Thor to be able to hold Loki and believe he was dead.
Finally, I was actually satisfied with how they managed the whole redemption thing. Loki wasn't and was (sort of) redeemed at the same time. The film did a nice job showing that while Loki did love Frigga and does care about Thor, his nature will never allow him a classic redemption arc. His mischief will always prevail but that doesn't mean he doesn't still have genuine emotion. I thought it was a nice play off the whole 'redemption equals death trope'.