How about arguments from analogy that are broadly evocative.
The underlying question seems to be:
To what extent should an agent's utility definition extend beyond their own person?
A ready example would be effective altruism - should an effective altruism care about bequesting their fortune after death, given that they are not around to process the outcome? Intuitively, subcultural conditioning would bring most people to say yes, but how about if I turned it around? For example, a suicidal woman may strongly advocate for a right to suicide. Would she be maximising her utility to publish a note to the effect of calling on potential like-minded suicidees to kill anti-suicide policy-makers/politicians before they kill themselves, in order to pressure them to change their stance and raise awareness for dying with dignity? The post-death value maximising approach should be consistent in both the EA and suicide example, I should think.
To what extent should an agent's utility definition extend beyond their own person?
I'm not sure how to evaluate "should" in the question, but most people I know (including myself) "do" include events they'll never directly perceive in their decisions.
Personally, I recognize that some of my current happiness and motivation is based on imagining potential future events that I think are exceedingly unlikely for me to actually experience. I make decisions based on likely impact on others outside of my perception-cone, such as strangers ...
Every so often, I see a blog post about death, usually remarking on the death of someone the writer knew, and it often includes sentiments about "everyone is going to die, and that's terrible, but we can't do anything about it have so we have to accept it."
It's one of those sentiments that people find profound and is often considered Deep Wisdom. There's just one problem with it. It isn't true. If you think cryonics can work, as many people here do, then you believe that people don't really have to die, and we don't need to accept that we've only got at most about a hundred years and then that's it.
And I want to tell them this, as though I was a religious missionary out to spread the Good Word that you can save your soul and get into Christian Heaven as long as you sign up with Our Church. (Which I would actually do, if I believed that Christianity was correct.)
But it's not easy to broach the issue in a blog comment, and I'm not a good salesman. (One of the last times I tried, my posts kept getting deleted by the moderators.) It would be a lot better if I could simply link them to a better sales pitch; the kind of people I'm talking to are the kinds of people who read things on the Internet. Unfortunately, not one of the pro-cryonics posts listed on the LessWrong wiki can serve this purpose. Not "Normal Cryonics", not "You Only Live Twice", not "We Agree: Get Froze", not one! Why isn't there one? Heck, I'd pay money to get it written. I'd even pay Eliezer Yudkowsky a bunch of money to talk to my father on the telephone about cryonics, with a substantial bonus on offer if my father agrees to sign up. (We can discuss actual dollar amounts in the comments or over private messages.)
Please, someone get to work on this!