Regardless of whether or not our beloved Frank is dead, I have a few things I'd like to point out about him.
This season, as I'm sure most of you have noticed, he's been painfully insignificant, occasionally coming forth with a witty one-liner. I feel like he played a drastically bigger role in the 4th season, where he was only a guest star. He's done nothing this season.
Similarly, he's the only main character of this season we haven't seen in the alternate timeline (save Richard and MiB, if you count him). Why? Everyone loves Frank. We got to see Frogurt, who I could care less about, but not Frank? That doesn't seem fair. Maybe we'll see him in the near future, seeing as we hadn't seen Ilana in the FS until the episode after her death.
On a much pettier note, why didn't he change clothes at the beach camp? His pilot shirt was all bloody and must have been pretty uncomfortable.
Also, did Frank just completely forget about the Ajira passengers? He was all for trying to protect them and get them off the Island in the 5th season. This season, he hasn't mentioned them once. Not once. Which doesn't make any sense. It would have only taken three lines:
FRANK: We can't forget to bring the passengers from Flight 316 with us when we leave the Island!
SAWYER: Sorry, but they're all dead.
FRANK: Aw, that sucks.
Similarly, why hasn't Richard tried to look for or inquired of anyone about the Others who were at the Statue with him? Doesn't he care about them? I doubt we'll ever figure out what happened to them, which kind of pisses me off. If you forget, Sun said they told her they were headed to the Temple in "The Substitute". But it seems that they never made it there.
Anyway, that's all I've got.