Re: the crystal barrier, Kal-L found it in the Kingdom. I tried to find the images on the Internet somewhere...but couldn't. He decided not to use it at that time, though.
So Mark Waid (surprise) initially set up the return of Kal-L. I think our conspiracy runs deep
However, I just read Infinite Crisis #2 this morning....
[[[OMG SPOILER ALERT!]]]] [[[[OMG, RUN AWAY IF YOU'RE SCARED!!!]]]]
and I'm a little cynical and worried. Infinite Crisis #1 was completely pessimistic until the end, when Kal-L returned. Crisis #2 was the opposite; it represented our point of view, that the comics world is devoid of optimism and joy, that Kal-L should fix it, and Power Girl's Earth-1 memory was restored in this issue.
Yet the end of it seemed ominous. Kal-L explained that the current earth is Earth-2, with aspects of the others folded in. (I like to think of "Whatever Happened to the Man of Tomorrow?" as the last Earth-2 story, but that's been re-retconned now. stinks to be me!) His solution? To bring back Earth-1. I have a scary feeling that Kal-L is going to take the same misguided path that Hal Jordan once took, try to restore his homeworld, and ignorantly spawn this new crisis. I really hope not, but despite all the optimism so far, "Crisis" is still in the title.
At the same time, Superman Chronicles is coming out next year. Why would they do that if there wasn't a market of people who wanted to catch up on Kal-L adventures? So I'm not afraid he's going to die. I'm afraid that the Crisis will be his fault, and he'll be tainted just like the others, which is a fate worse than death.