I am afraid the Widmore thing may be part of the over all story that they deem was already explained.
He lived on the island, had to leave the island, and has been obsessed with getting back ever since. I have a feeling his little rivalry with Ben which at one point seemed like it might perhaps be the biggest part of the Lost puzzle, will be down played to a fairly simple rivalry between two powerful men.
Maybe I am wrong, I hope I am. With this whole white vs. black thing going on, I have a hard time seeing how they are going to get around to explaining the Widmore thing beyond that.
The problem is this show spent way too much time building up mysteries, making everyone think the tiniest little details were important... and well, I am pretty sure all those folks obsessed with watching every episode a minimum of three times just to make sure they didn't miss any important details (such as a crate of oranges from a Kate flash back which supposedly took place in 1993 bearing the date 2006! *Gasp!* that definitely has to be of some significance to the mythology of the island!) are absolutely going to hate this show and mourn the time they wasted on it when all is over and done.
If they really do want to explain all the little things, like the Bible and glass eye Mr. Eko found, or the reasons the film strips were spliced, etc. then they will probably have to use a BSG style catch-all such as "That was Mr. Smokey manipulating things and trying to lead the castaways to discovering the islands secrets! He let the polar bears out, he made the Hurley bird say 'Hurley', he made the birds come to Walt, he made Walk appear 'Where he was not suppose to'..." Well, at least this show is still a hell of a lot more interesting than BSG was in its last of days (as much as I loved watching long drawn out scenes of Adama balling his eyes out while in a fetal position on his bathroom floor every other episode...).