Look, I know how it's important to US, as fans of the Star Trek franchise, for him to attend Nimoy's funeral... but when you get down to it, this is a REALLY personal thing. Nobody has a right to tell another person how or when to pay their respects.
Myself, I have never attended a funeral, and I don't expect to do so...ever. Not because they're meaningless to me, or because I'm insensitive. I just choose not to stand on ceremony and grieve in public. I absolutely MUST deal with these things in private. If you ever gave ME shit about it at a very vulnerable time, like some of Shatner's fans are on Twitter, they'd probably be putting TWO people in the ground. :P
I'm not suggesting that's what Shatner is dealing with. We don't actually KNOW what his true feelings and motivations are. I'm saying don't put so much weight on being physically present somewhere in order to pay your respects.
That said, there's another angle to this that I don't think many people really think about.
Personally, I never got the impression that Nimoy and Shatner were quite as like-family close as we'd all like to imagine. Undeniably, they have a famous, shared history, and they seemed to get along well.
But, behind the scenes, who's to say Leonard wasn't just this guy he worked a lot with over the years and occasionally meets up with to promote stuff together?
Being at his funeral might not be as important for him, personally, as it is for US. If that's the case, that disappointment is ours to bear, not his. That's not to say it won't be a terrible PR move. He'll definitely catch shit from his audience over it, if that's how things really are for Bill.
Anyway, the guy tried to get head of the wave by admitting his inability to attend via Twitter, and tried his best to improvise, staging a virtual memorial through his account.
There's not really much more you can ask, except for us to just move on.
UPDATE: Turns out he DID go. Hopefully on his own terms, and not because the disgusting media and incredibly rude fans were pressuring him to do it.
Every Trek movie, save for perhaps The Voyage Home, has been an action movie.
None of these really fit the traditional high-concept ideas usually attributed to the television version of Star Trek.
Insurrection comes close, mostly because they did that plot once already ("Homeward"). But it's still boils down to a rebellion and combat sequence by the end.
The original Motion Picture is another close one, however glacial the pace. Definitely the most cerebral of the franchise, if you can take enough caffeine to keep yourself awake through to the end.
The Voyage Home is the least violent, yet possibly most generally well-received out of all of the pre-Abrams movies. Combat generally comes down to Gillian Taylor slapping that guy at the aquarium, and a mannequin of Chekov being thrown off the edge of a platform.
Wrath of Khan is the undisputed fan favorite. And that was a bloody, violent war flick.
Complaining about Abram's take on Trek because of it's focus on action is basically damning the majority of the movie franchise. Star Trek movies are a completely different animal from it's television incarnation.