So with 7 episodes left until the end, I was thinking about which characters will get their own centric episodes. I seriously doubt they are going to devote another episode to the flash-sideways that we've already seen. That would rule out Jack, Locke, Kate, Sayid, Sun, Jin and Ben. Richard, more than likely, will not be given a flash-sideways. So who is left? I'm thinking Hurley has to be given an episode soon, considering the fact that he is a candidate, and definitely Desmond after his re-introduction at the end of "The Package". But who then? That gives us five episodes. Let's look at the remaining characters:
Miles - in my opinion, fairly irrelevant at this stage. Plus he shared a flash-sideways with Sawyer already. Not worthy of a centric episode.
Frank - the pilot with the great one-liners. It's possible he will be given a flash-sideways, perhaps as maybe a filler episode setting up the premise for the final showdown.
Ilana - I would love for her to get a flashback. For me, this is very likely after seeing that brief scene with her and Jacob in the Russian hospital. Jacob said that the protection of the candidates was the moment she'd been waiting for. I would love to see her relationship with the Island's protector explored further, and I consider this to be a probability moreso than a possibility.
Charles Widmore - Again, very possible. A flash-sideways would give us valuable insight into his position relative to the sunken Island in the FST, and furthermore giving us further information as to when the Island sunk. A necessity, perhaps. Again, very likely.
Zoe - Not very likely. Her character lacks any real depth, but seeing as she was only introduced in "Recon" that's hardly her fault. A small possibility, another potential filler episode setting up the premise for the finale.
Man in Black - 100% necessity. But unsure as to whether is should be a flash-sideways or flashback, depending on how the plot progresses. Some people have theorised that the FST is a result of the MiB being unleashed on the world, so perhaps we will see his direct involvement in the FST characters' lives. A flashback to his childhood, as a mere mortal may be a stronger possibility however, and I would hope to see that the identity of the boy will be revealed.
After these, I can't think of any more, unless I missed someone. I would consider the Man in Black, Ilana and arguably Charles Widmore to be necessities in order to make the fabric of the show come together in its last few outings. But I would be disappointed if we are treated to any two of Miles, Frank and Zoe, because, despite the fact that they are humorous characters who add a touch of realism to the show, their roles are (so far) too insignificant in the the ongoing conflict to be given an episode dedicated entirely to themselves.