If there were a separate Hardcore server, upon death, that character gets a free server transfer to a non-hardcore world of your choice (that's not currently overpopulated).

If you were on regular servers and you died, you just lose Hardcore (Immortal?!) status on that character and any rewards that you've suggested, such as title/mount/whatever, permanently disappear.

I think people would be much more inclined to give that a go.

Also to those saying "to learn fights/dungeons you have to die" - sure, but mayhap your 'hardcore' character is an alt wherein you've done those runs 100x on your main and are well-versed in their execution.