I'm not a Ramamia user, so please excuse it if my comments seem ignorant; they are. I'm just thinking about what my family would want/need. If it's slick enough, we might become users one day. As far as I'm concerned, you'll have to beat the MobileMe/iPhoto combination, which is still very much one-way, but extremely easy to use.

Some family members want to download and share pictures. I have explained that that's not what this site is for.

This is a must. Save the original files when they're uploaded, even if you then show downscaled versions to users on the web interface: have a prominent "download printable version" link/button. Also: have a button for downloading a whole album as a zip file or whatever. You're charging people, so suck up the extra traffic and storage.

Killer: have an "order a [framed/unframed] print of this" button for those who don't have a photo printer and glossy paper. Interface with a third-party printing service for this, get commission for it.

Speaking of iPhoto: importing albums straight from iPhoto would be fantastic. This is technically possible from a Java Applet or maybe via Flash, but prepare to sink quite a bit of effort into it if you decide to try this. Let me know (email in profile) if you need any pointers.