I've always thought that funerals are for the living, so I think it's best if people just do it how they see fit. If someone doesn't want to come, fine! We all grieve differently and I wouldn't want anyone to be dragged to the funeral they find hard to attent. For some funeral is closure, some want photos and slideshows, I know a lady who made a Smartshow 3d slideshow of her photos herself (in her words, "They'll never pick the photos I like, so I'll do it for them"), and some want none of this.
It's just so deeply personal that there is no "right" or "wrong" imo.